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Chapter 21: Plants of medicine, culture, and industry.

Human society has had, from the beginning, a strong dependence on the botanical world, especially for food and wood products. If primitive humans found plants that eased pain, soothed stomach distress or provided relief of any kind, it was undoubtedly an accidental discovery. Disease per se was not understood at the time. Physical ailments were mystical and therefore were attributed to "bad spirits" or as punishment from displeased supernatural powers. Once plants that were effective in relieving human suffering were identified, knowledge of their healing properties was passed on through generation by word of mouth and later in written form.


After completing this chapter, you should be able to:

* Discuss the history of herbalism and medicinal plants

* Name places where medicine men are used as doctors today

* List documented plants that have medicinal compounds

* Name some of the curative powers of plants

* Discuss the psychoactive plants

* Discover the types of compounds in plants that are poisonous

* Describe plants that are toxic to internal organs

* Identify plants that have industrial importance

Key Terms

doctrine of signatures


pure opium













cardiac glycosides


anthraquinone glycosides


oxytocic agent











d-lysergic acid diethylamide (LSD)

fly agaric










somatic nervous system

autonomic nervous system

central nervous system











carnauba wax


History of Herbalism

The early history of plant science was essentially the early history of medicinal plants, and the use of plants for treating ailments was the realm of the botanist. In the first century AD, Dioscorides compiled detailed botanicals and medicinal information on thousands of plants in his De Materia Medica. This book was to remain the authoritative reference on medical plants for over 15,000 years. In the fifteenth to seventeenth centuries, botany became more of a science, and the use of medicinal plants was finally a mixture of medical knowledge and ritual, not exclusively a magical practice. Herbalists were a combination of botanist, psychiatrist, and faith healer, but their knowledge of the effect plants had on the body was considerable. As more was learned about the true medicinal value of plants, less credence was given to those having only mystical powers. This was the beginning of disenchantment with much of "traditional" medicine. Early in the twentieth century, only a few medicinal plants of exceptional value and proven effectiveness continued to be recognized. However, midway in the twentieth century, the "baby boomers" started to show signs of aging, plus a continued pursuit for organic and natural foods. The medicinal effect of these natural herbs had an appeal. Most of these homeopathic herbs had not been clinically tested; little basic research has been conducted on most of the herbs used for medicinal purposes. There are approximately five to eight medicinal herbs that have been subjected to this needed research.

Modern medicine is predominately composed of scientifically developed synthetic drugs, although about 40% of all prescribed drugs are natural substances or only semisynthetic. Medical schools generally offer only a single course (pharmacognosy) dealing with medicines directly from plant, animal, and mineral origins. This has been the case for only a little over a hundred years, throughout history, and even in many cultures today, the physician has been a person with excellent knowledge of botanical knowledge.

The medicine men of the American Indians, the witch doctors and herbalists of Africa and South America, and the shamans of Asia, as shown in Figure 21-1, trained practitioners who function not only in the realm of mystical and occult faith healing. Many years of training and apprenticeship are required before an individual is recognized as a medicine man or herbalist. Navajo medicine men, for example, learn about the biology and uses of over 200 different plants during their training. Their African and South American counterparts have comparable knowledge of the medicinal plants found in their parts of the world. The Miskitos of eastern Nicaragua, although occupying a very small geographical area, have medicinal uses for almost 100 different plants. Much as modern medicine often must rely on trained counselors, psychiatrists, and psychologists to treat symptoms involving the mind and the emotions of the patient, the herbalists and witch doctors have always considered treatment of their spirit an integral part of their craft. The modern Navajo Indians often blend the two worlds of medicine. The physician deals with most of their physical needs, including surgery. While the medicine man treats imbalances in body functions with his herbal teas and poultices and tends to the health of the mind and spirit.


Nowhere has a balance of traditional medicine and modern medicine been achieved with greater success or overall acceptance than in the People's Republic of China. Few cultivars have a more thorough knowledge of herbal remedies. Along with acupuncture, this knowledge forms a solid base for their total health care. Both the traditionalists and the modern medical people accept the strength of each other's expertise, knowledgeably blending them into an approach to treatment of the whole entity--the human body, spirit, and mind. Holistic medicine is gaining in acceptance by many Western physicians, and the World Health Organization (WHO) now sponsors a program to promote and encourage traditional medicine throughout the developing countries of the world. Biomedical scientists and other health experts are showing increased interest in the plants used by health experts. The plants used by reputable herbalists and biological conservationists are receiving increased support and acceptance of their efforts to prevent plant extinction, especially in the tropics. It is estimated that 20,000 species of flowering plants are threatened because of clearing the forest for agriculture and development. It is not known how many plants may exist with as yet undiscovered potential for food, industrial, or medical use. It will never be known if these plants become extinct. The renewed interest in medicinal plants is therefore a timely and desirable activity while both the plants and the lore about their medicinal use still exist.

Medicinal Plants

A degree of difficulty exists in categorizing some plants as medicinal plants, psychoactive, and poisonous dosages. For other plants, the distinction is clear. It should be noted, however, that essentially any chemical substance added to the body could be toxic or harmful in excessive amounts.

Mandrake (Mandragora officinarum)

Although mandrake was written about more extensively than any of the early medicinal plants, its use was surrounded in myth and superstition. Appreciation of this plant goes back to several hundred years BC, and its use in ancient Rome is documented. The active compounds are several alkaloids, primarily hyoscyamine. They may be extracted in great quantities from the root by soaking or boiling in wine. This extract was the first effective anesthetic, sedative, and pain reliever.

Because mandrake root was so potent and because of the lack of understanding of its properties, mandrake was then considered a mystical plant. A mandrake root was a good luck charm, endowing its prowess and great wealth. A popular belief of this time was the doctrine of signatures, which stated that the Creator placed certain items on Earth for humans and identified their intended use by their shape. A kidney-shaped leaf was considered to be useful in treating the kidney; walnuts, with their furrowed ridges, were believed to be beneficial to the health of the brain or head; and liverworts were used to treat the liver. The shape of mandragora frequently resembled the human body, with a thick, fleshy, two-branched or forked taproot and a short stem branching into the leafy part of the plant. It did not take too much imagination to conceive of this as a human form--thus, mandragora was believed to benefit the entire body.

Biblical scholars think mandrake might have been offered to Christ on the cross to ease his pain. Shakespeare detailed important considerations in collecting the root: It must be accomplished without listening to its death shriek as it is pulled from the ground, lest the collector die of fright from the horror of the sound. Lucrezia Borgia (most ruthless of Italian Renaissance noblewomen) used mandrake as a poison. Even in the nineteenth and twentieth centuries, extract from mandragora root have been mixed with morphine to produce a twilight sleep to ease the pain of childbirth.

Duboisia (Solanaceae)

In its native Australia, this plant was used by aborigines during the same period of time that mandrake was used in Europe, the Middle East, and North Africa. Also containing hyoscyamine, the leaves were used to relieve pain. The hunters ran their prey into exhaustion, which often took several days. Once the kill was made, the hunters would chew Duboisia leaves to ease the fatigue, hunger, and thirst from their exertions. They also used it to stupefy the emu and to poison fish.

Cinchona (Rubiaceae)

Native to tropical South America, this tree contains the alkaloids quinine and quinidine in its bark. Prepared commercially as early as 1823, quinine was used for over a hundred years to treat hundreds of thousands of malaria victims. After 1920, a synthetic chloroquine has been preferred for the treatment and suppression of malaria.


Cinchona was named by Linnaeus for the Countess of Chinchone, wife of the Viceroy of Peru. The countess was cured of a malarial fever in about 1638 by a tribal witch doctor (who the Viceroy subsequently appointed as the royal physician). Following a visit to Peru, King Charles II of England and several members of the French and Spanish royal families contracted the dreaded yellow fever (malaria) and sent word to Peru. The viceroy, the countess, the witch doctor, and a support entourage set sail to Europe, taking with them an ample supply of the bark. After successful treatment of King Charles and the others, the drug became widely acclaimed in Europe. Drawing the attention of Linnaeus, who named the plant and described it based on the witch doctor's description and bark samples. Later, Linnaeus sent students, to Peru, to collect botanical specimens at the invitation of the countess.

Opium Poppy (Papaver somniferum, Papaveraceae)

Opium poppy, a native Middle Eastern plant, contains over 25 different alkaloids, including several that are among the most important pain reliever in human history. The immature capsules yield a milky sap when cut. This sap dries to a gummy brown residue of pure opium. Known to the Sumerians as early as 4000 BC, opium, as shown in Figure 21-2, was used medicinally in ancient Greece, Rome, and China. During the Middle Ages, laudanum (opium dissolved in wine) was widely used to relive pain and produce a euphoric state.


From opium several powerful alkaloids can be extracted, the most important being codeine, morphine, and heroin. All these compounds are analgesic (pain relieving), affecting the central nervous system. Codeine is the mildest of these, producing almost no euphoria but effectively relieving minor pain and functioning as a cough suppressant.

Morphine depresses the cerebral cortex, reducing brain arousal to pain and causing a euphoric feeling, thus eliminating anxiety. Morphine also depresses the respiratory and cough centers of the brain and impairs digestive action. Prolonged use of morphine results in physical tolerance, so gradually increasing dosages are necessary to achieve the same pain relief. Prolonged use also results in addiction, which at one time was common in wounded soldiers. As with any addictive narcotic compound, discontinued use results in physical painful withdrawal symptoms.

Heroin, a product manufactured from opium, is so powerful in its effects on the body and so dangerously addictive, it is not used medicinally even by prescription in the United States. It is available only through illegal means, so the price is high and the quality and purity are erratic. As with morphine, the body builds a tolerance to heroin and requires increased dosages to produce the same effect. Advanced addiction requires such large quantities that overdoses frequently occur. Thus, from a single plant species, Papaver somniferum, some of the most widely used pain relievers and most dangerous addictive drugs originate.

By the nineteenth century, "medical" opium use was widespread in
Europe and North America, producing thousands of opium addicts,
many who were prominent and wealthy. Opium use, however, was far
more common and serious in China than anywhere else. There, it was
smoked in specially constructed pipes, addicting millions by the
1830s. Although opium was banned in China by the last Ming emperor
(1628-1644), British and American clipper ships nevertheless
smuggled tons of opium from India into China for almost two

Beginning with territorial conquest in India in 1757,
the British East India Company pursued a monopoly on opium
production and export in India.

Due to the growing British demand for Chinese tea, and the Chinese
refusal to accept payment other than silver bullion, the British
sought to substitute another commodity for which China was not
self-sufficient to alleviate the silver drain--a burden on the
British economy. Opium was successfully used by the British traders
to replace silver in exchange for Chinese tea for a period of
decades. The product was sold by the chest in auctions in Calcutta
and then smuggled into China. The East India Company used the
profit to purchase teas that were in high demand in Britain. This
illegal trade became one of the world's most valuable single
commodity trades.

Many Chinese became addicted to opium, wreaking
havoc among much of China's population. In response, the Imperial
Qing dynasty halted the import of opium, demanding silver be traded
instead. Lin Tse-hsu became the imperial commissioner at Canton.
His purpose of seeking this appointment was to cut off the opium
trade at its source by rooting out corrupt officials and cracking
down on British trade in the drug. He took over in March 1839 and
within two months he had taken action against Chinese merchants and
Western traders and shut down all the traffic in opium. He
destroyed all the existing stores of opium. Also Lin was absolutely
invulnerable to bribery and corruption.

This response led to the Opium Wars, since the British were not
willing to replace the cheap opium with costly silver. The First
Opium War won by Britain led to seizing Hong Kong (returned to China
in 2002) and to what the Chinese term the "century of shame." The
Second Opium War occurred 10 years later, followed finally by the
Boxer Rebellion, during which the Chinese evicted all foreigners.
Seldom has a single plant affected so many or resulted in such

Belladonna (Atropa belladona, Solanaceae)

Like Mandragora and a number of other plants in this family, belladonna, shown in Figure 21-3, contains several powerful alkaloids, including hyoscyamine, scopolamine, and atropine. These alkaloids produce flushed skin and dilated pupils and with lethal doses, delirium and respiratory failure. Atropine specifically blocks parasympathetic nervous system effects and is used as an antidote to nerve gas poising. Spanish women used it in eye drops to dilate the pupils, thus achieving a large dark-eyed look; hence the name belladonna, Spanish for "beautiful women." Ophthalmologists take advantage of its pupil-dilation properties to facilitate examination of the interior of the eye.

Curare, (Chondodendron tomentosum, Menispermacear)

Chondodendron tomentosum is a native of South America and produces the alkaloid tubocurarine, the principal ingredient in curare. Curare interferes with nerve impulses to the skeletal (voluntary) muscles, producing a reversible paralysis. This drug has been used as a muscle antispasmodic in the treatment of rabies and in spastic conditions. It can also induce muscle relaxation during surgery without anesthesia, and helps control convulsions caused by poisons such as strychnine.


Rauwolfia (Apocynaceae)

This plant is native to Africa and Asia, where extracts have been used by the shamans (herbalists) to treat nervous hypertension. Rauwolfia is responsible for initiating serious consideration of plants long used by herbalists. Some 50 alkaloids are present in the several species of this genus, but reserpine is the medical agent responsible for lowering blood pressure. It acts by blocking impulses in the sympathetic nervous system, thus lowering blood pressure by relaxing the vessels. It also has a sedative effect on a part of the brain that controls tension. Its use in patients with mental disorders related to hypertension as well as those with high blood pressure makes this a valuable medical plant.

Ephedra (Ephedraceae)

Species of ephedra (see Figure 21-4) (a gymnosperm) from India and China contain an alkaloid amine, ephedrine, that acts as a bronchodilator. Its mode of action is to relax the smooth muscles of the bronchial tubes, increasing their diameter and improving passage of air through them. Patients with bronchial asthma, chronic bronchitis, and emphysema are treated with this drug.


Several species of ephedra also occur in western North America, but they have only small traces of ephedrine, so their effect as a bronchodilator is minimal. A tea is made from these plants, however, that is an effective diuretic. Ephedra and ephedrine are both used as dietary supplements for weight loss and enhancement of physical activities. December 29, 2003, the FDA banned the use of ephedra in any products, because of the risk of heart attacks caused by taking products that contain ephedra.

The FDA have not evaluated data concerning the safety or purported benefits of most dietary supplement products. The law provides that the manufacturer must make sure that label information is truthful and not misleading. The manufacturer is also responsible for making sure that the dietary ingredients in the supplement are safe. Manufacturers and distributors do not need to register with the FDA or get FDA approval before producing or selling dietary supplements. However, the FDA has proposed rules for dietary supplements containing ephedrine alkaloids. These proposed rules would require warning statements about the amount of alkaloid in a serving of the supplement on the label of all dietary supplements containing ephedrine alkaloids. It should also give the amount of the supplement that is safe to take.

Foxglove (Digitalis purpurea, Scrophulariaceae)

Native to Europe and shown in Figure 21-5, this exceptionally valuable medical plant contains several cardiac glycosides, including digitoxin. Prior to the discovery of this drug, thousands of people died each year from congestive heart failure, the inability of the heart to pump blood at a sufficient pressure. This resulted in edema, or fluid buildup in tissues throughout the body, often causing such a swollen and distorted body that movement was difficult. The ailment was known commonly as dropsy. Treatment with digitalis slows and strengthens the heartbeat, which increases the volume of blood being circulated through the body. The filtering activity of the kidneys and the blood is more effective in removing wasters and preventing fluid buildups. It is estimated that, in the United States alone, over 5 million heart disease patients daily use digitoxin, or one of the other cardiac glycosides found in this plant.

Senna (Cassia senna, Fabaceae), Cascara (Rhamnus cathartica, Rhamnaceae)

These and several other species in these two genera contain anthraquinone glycosides, which produce compounds having a strong purgative action. Constipation can be treated with these plants because they enhance peristaltic action of the colon. Several Cassia species have been credited periodically with special powers--as aphrodisiacs, venereal disease cures, and effective poultices for wounds and bleeding.


Ergot (Claviceps purpurea)

This fungus infects wheat, rye, and other cereals, destroying the seed and producing a black spore--containing sac in its place. These spores contain two alkaloids. One of these, ergonovine, has been an effective oxytocic agent, stimulating uterine contraction and speeding up labor. Ergonovine is more effective in this capacity than the animal hormone oxytocin, and it also reduces postpartum bleeding, has low toxicity, and acts rapidly. Ergot also has an interesting history as a hallucinogen.

Herbal Remedies

Besides the well-known and effective medicinal plants just discussed, there are hundreds of undiscovered and poorly understood herbal remedies. Fortunately, few of these plants have toxic or addictive dangers.

Table 21-1 lists a small percentage of the plants reported as having some medicinal value in the United States alone. There are many popular books detailing the correct collection, extraction, and use of these and many more herbal remedies; however, great care should always be taken when collecting your own. An intelligent combination of home remedies and health tonic with modern medical care is becoming a popular and widely accepted health care plan in the United States. Certainly, there is room for more scientific and biomedical study of many of these herbal cures and the plants used in their preparation.

As the baby boomers starting to show signs of aging , an increase in the use of many herbal dietary supplements escalated. What is a dietary supplement? The most logical definition would be something that supplies one or more essential nutrients missing from the diet. However, the Dietary Supplement Health and Education Act of 1994 (DSHEA) defines a dietary supplement as any product (except tobacco) that contains one of the following: (1) a vitamin, (2) a mineral, (3) an herb or botanical, (4) an amino acid, (5) a dietary substance "for use to supplement the diet by increasing total intake," or (6) any concentrate, metabolite, constant, extracts, or combinations of any of the aforementioned ingredients. Herbs, of course, are not consumed for a nutritional purpose and often are marketed with therapeutic claims. The supplement industry, which lobbied vigorously for passage of the act, included them in the definition to weaken the FDA's ability to regulate their marketing. Since the DSHEA's passage, hormones have also been marketed as dietary supplements.

Psychoactive Plants

Psychoactive plants contain compounds that act on the central nervous system to produce a mind-altering state, visions, distortions of the sense, and changes in psychomotor ability. There are three categories of psychoactive compounds: stimulants, hallucinogens, and depressants. It is not uncommon, however, for all psychoactive compounds to be considered hallucinogenic because of the mind alteration produced. The drug culture of the 1960s and 1970s dubbed these experiences "trips" and called some of these compounds "mind expansion" or "psychedelic" drugs. Modern Western culture developed new terms, new uses, and some new synthetic drugs, but psychoactive compounds have been in use for thousands of years. Hallucinogens have been a part of religious activities of many cultures, especially the more primitive ones, for a long time. Social use of such drugs has also been a regular part of many of the more advanced societies throughout history. Drug use has been acceptable in ceremonial and ritualistic context; however, it has varied from widely acceptable to forbidden and illegal in social settings.

Many of these compounds come from plants. Some of those considered to be hallucinogenic have had medical applications in lighter dosages. Mandrake and belladonna in Solanaceae fall into the medicinal, hallucinogenic, or poisonous category, depending on dosage. Others, while having no medicinal value per se, have been used to treat mental disorders and as pain relievers by altering the patient's level of consciousness. Still others are not hallucinogenic but poisonous. These are sometimes called pseudohallucinogens because they produce a delirium while acting on the system. The delirium makes the user very sick, and the after effect is painful. Nutmeg is a pseudohallucinogen, attractive for its availability and nominal cost. Several tablespoons, if it can be kept down, produces a painfully nauseating delirium from which the user comes down "hard" with a severe and extended pain toxic recovery.


Sedatives and Stimulants

Although categorized by many as hallucinogenic, opium and opiate derivatives are not; they are sedatives, often producing a relaxed euphoric state but no true consciousness alteration. Reserpine, the indole alkaloid form of Rauwolfia, is also a depressant and lowers blood pressure. Alcoholic beverages have depressant action reducing both mental and physical performance levels. Since alcoholic beverages all come from the fermentation process using plants as the sugar source, alcohol can be considered a plant product.

A drug that falls into the stimulant category is cocaine. Extracted from the leaves of Erythroxylon coca, as shown in Figure 21-6, a plant native to the eastern slopes of the Andes Mountains of South America, cocaine produces a feeling of euphoria, a lessening of fatigue, an absence of hunger, and increased energy. Cocaine does not produce a hallucinogenic response, is not normally physiologically addictive, and the user does not require increasing quantities due to body tolerance. It is, however, psychologically addictive, and strong doses can produce feelings of paranoia and nervous insomnia. It also damages the mucosal tissues of the nose and throat, sometimes permanently destroying these sensitive areas.

Indians in the Andes Mountains chew the leaves, which enables incredible feats of endurance without food or rest. Coca chewing is common among the people of this region, as much a cultural phenomenon as an aid to extensive manual labor. It is reported that some of the early popularity of Coca-Cola in the 1870s was because a small amount of cocaine was included in the recipe. Cocaine was banned as a component of the drink in the 1900s.



Hallucinogenic compounds distort the senses, especially visual, and produce a departure from reality. The plants that contain these compounds are all angiosperms, predominately dicots. There are no known hallucinogenic gymnosperms, ferns, bryophytes, or algae, but the fungi include a number of hallucinogenic taxa. Depending on the organism and the part that contains the active compound, one can eat the fresh or dried plant, chew the appropriate plant parts, concoct a beverage, inhale a powder, smoke the leaves, and even smear an oil-based ointment on the body.

Marijuana (Cannabis indica; C. sativa)

More than three species of Cannabis, as shown in Figure 21-7, are recognized, depending on the legalistic or scientific (often mixed) point of view. Cannabis sativa is the best known species although C. indica contains a higher concentration of the active compound. C. sativa is an erect species with many fiber cells in the stem, a commercial source for making hemp rope, paper, and canvas. C. indica is a low growing, highly branched species containing high levels of trans-tetrahydrocannabinolic acid, which converts on heating to tetrahydrocannabional (THC), the compound that produces the hallucinogenic effects. THC is found in greatest concentration in glandular hairs on the leaves, stems, and especially on the small bracts just below a pistillate flowering inflorescence. When collected from the glandular hairs separately, it is much more potent and is called hashish.

The physiological effects of THC on the body include an increased pulse rate, reddening of the eyes and possibly a reduction in the internal fluid pressure of the eyeball. Marijuana is credited with enhancing visual perception, reducing muscular response time and coordination, altering time perception, increasing one's inner awareness, removing tension, and increasing sex drive.

THC is not an alkaloid and is not considered toxic or physiologically addictive. Its classification as a narcotic, therefore, is a legal category and not a chemical group. Psychological dependence, however, is not uncommon.

Arguments abound today: Is marijuana a dangerous drug or a mildly hallucinogenic compound less harmful than tobacco or alcohol? Cannabis is probably the most widely used and highly valued multipurpose plant in history. It has served as a source for fiber, as a medicine, and as a mild hallucinogen worldwide since it was introduced into North America in 1607. Only illegal as a crop plant since the late 1940s, over 63,000 tons of hemp (C. sativa) were raised in 1943 to provide the Navy with rope during the war. George Washington also raised hemp on his Virginia farm. There is still the push to legalize marijuana for it medicinal properties. Research has shown that marijuana helps to control some of the side effects of chemotherapy. It has been legalized for this purpose only in a very few states.


Ergot itself is not the hallucinogen but is the spore-producing reproductive body of a fungus, Claviceps purpurea, that affects rye, wheat, and other cereal crops. Within the sacs are millions of tiny black spores containing several alkaloids, including ergonovine. Chemically known as lysergic acid, it is very similar structurally to a synthetic compound, d-lysergic acid diethylamide (LSD). Ergonovine produces smooth muscle and blood constriction, which causes a burning sensation. Eating infected grain produces the disease that is known as St. Anthony's fire, which could result in gangrene of the ears, nose, and other body extremities from lack of blood flow through the constricted vessels. This disease was thought to be caused by bad grain (the ergot sacs were mistaken

for diseased grain), thus, indirectly an affliction from the devil. Victims would visit monasteries to repent and have the evil forces driven out. When fed with uninfected grain and given adequate fresh water and rest, most people would recover, but sometimes with the tip of their nose or ear or even a hand or foot missing.

In addition to the burning sensation and danger of gangrene, the victims of St. Anthony's fire had hallucinations, an effect of the poisoning and the lysergic acid. LSD, on the other hand, is a much more powerful synthetic relative and a popular modern hallucinogen.

Fly Agaric

The fly agaric mushroom is another hallucinogenic fungus (see Figure 21-8). Scientifically known as Amanita muscaria, these attractive mushrooms are large, bright yellow to orange-red with small white speckles on top. Their common name comes from the dead flies that are often found on the ground around them--in addition to being hallucinogenic, they are poisonous. Only the ones growing in the Old World are psychoactive, containing the alkaloid muscarine. This is the only known hallucinogenic compound that passes through the kidneys unaltered, and some cultures have been known to reuse the compound several times by drinking urine.


In larger doses, muscarine produces blurred vision, sweating, lowered blood pressure, slow heartbeat, stomach pain, and breathing difficulty. These are the opposite symptoms of atropine poisoning, and fly agaric is used as an antidote to atropine overdoses.

Sacred Mushrooms

Several genera of mushrooms containing the alkaloid psilocin and psilocybin were used to produce hallucinogenic visions. The "mushroom cults" of modern times have most commonly used Psilocybe mexicana although Conocybe and Stropheria also contain significant levels of these alkaloids. These cults were originally a blend of Christian and pagan rituals, but today they are almost nonexistent found only in a few villages in the northeastern mountains of Oaxaca, Mexico.

During the Mayan period in Mexico, mushroom use was common but officially available only to the priest. In contrast, almost anyone could use sacred mushrooms during the Aztec era. Some authorities believed that widespread mushroom usage was associated with the Aztec practice of offering human sacrifices by the hundreds to the gods. Current descendants, the Mazatec Indians of Oaxaca, believed that the mushrooms may be eaten only at night, and the activity is now a closed family affair.


Figure 21-9 shows Lophophora williamsii, which is a small, rounded, spineless cactus that grows flush with the ground, and is found in the southwestern United States but grows primarily in Mexico. The hallucinogenic compound found in the peyote is the alkaloid mescaline. The Aztecs used peyote as did the Comanches under the leadership of Chief Quanah Parker, who in 1875 was the last Indian chief to surrender his people to confinement on a reservation. It is now most closely associated with the religious rituals of North American Indians belonging to the Native American Church. Known for its nauseatingly bitter taste, peyote can be eaten fresh or the dehydrated buttons can be chewed to achieve the desired effects. A drink can also be made from the buttons, but it is reportedly less effective in producing the vivid hallucinations. Bad trips are possible, as are spontaneous flashback recurrences.


Solanaceae: Henbane, Belladonna, Mandrake, and Thorn Apple

Henbane (Hyoscyamus niger), belladonna or deadly nightshade (Atropa belladonna), Mandrake (Mandragora officinarum), and thorn apple or jimsonweed (Datura spp.) are all members of the same plant family. They all contain alkaloids including scopolamine, hyoscyamine, and atropine (hyoscyamine in the fresh plant changes to atropine when the plant is dried). These compounds have been used medically, hallucinogenically, and as toxins throughout history.

In mild doses, a feeling of timelessness and high spirits accompanies visual hallucinations and the sensation of flight. These plants were once a common ingredient in "witch's brew." When painted on the body with a straw broom, the alkaloids were absorbed through the skin and produced these reactions. The image of witches flying on broomsticks is a carryover from this ritual.

Other Hallucinogens

Other hallucinogenic plants include the South American Virols of the nutmeg family, which is administered to others by blowing a powder extracted from resin in the bark up the nose through a hollow snuff tube. Another South American plant, Banisteriopsis, yields an intoxicating beverage that produces a wide range of hallucinogenic responses. The Aztecs also used morning glories (Ipomoea violacea and Rivea corymbosa), shown in Figure 21-10, which contain alkaloids similar to lysergic acid and its relatives.


Today's ornamental varieties often contain these compounds and are known by common names such as "pearly gates" and "heavenly blues." North American Indians used mescal beans (Sophora secundiflora) before they began to use peyote. Peyote was preferred because of the high toxicity of mescal beans. Interestingly, these two plants were often found in identical habitats, and the Indians believed that the easily visible mescal bean plants were provided to lead them to the peyote cactus growing near them. They wore necklaces made of mescal beans during their peyote rituals.

Poisonous Plants

Of the approximately 500,000 plant species in the world, less than 1% of them are thought to be toxic to humans. In spite of this statistic, poison control centers in the United States find that plants consistently rank in the top three as sources of possible poisoning; for children under 5, plants are the number one danger. This is a result of the significant increases in numbers of houseplants in homes, offices, and malls.

Historically, poisonous plants have been less a problem of accidental consumption than a purposefully ingested agent for medical or hallucinogenic purposes. The chemistry of plant toxicity is much better understood today; hence, the reduced number of accidental poisonings resulting from incorrect dosage types.

Classes of Poisonous Compounds

Plant-derived medicines include a variety of chemical compounds. Some of these can be poisonous if not taken as directed. Following is a list of compounds and the plants they are derived from.

Internal Organ Poisons

These act primarily on the kidneys, liver, and stomach and include several distinct chemical types.

1. Alkaloids contain nitrogen and usually taste bitter. They are commonly found in several plant families, including the Solanaceae, Fabaceae, Papaveraceae, Rubiaceae, Apocynaceae, and Ranunculaceae.

2. Glycosides

a. Cyanogenic glycosides included hydrocyanic acid (HCH), found in peach and cherry pits.

b. Cardiac glycosides are the compounds found in Digitalis. They affect the heart.

3. Oxalates (oxalic acid) are found in rhubarb leaves and several other plants and produce severe stomach pain.

4. Resins are found in milkweed, laurels, and water hemlock and are especially potent toxins.

5. Phytotoxins are proteins, such as the active ingredients of castor bean plants.

Nerve Poisons

These are alkaloids: The toxin acts on different parts of the nervous system.

1. Somatic nervous system toxins act on the striated skeletal or conscious control muscles. Curare is an example in this category.

2. Autonomic nervous system toxins affect the smooth muscles of the heart. An example is alkaloids of the Solanaceae.

3. Central nervous system toxins, the opiate group, act on the brain and spinal cord.


These compounds burn the skin, eyes, and throat, usually causing swelling, redness, welts, and even weeping lesions. Many are resins.

Mineral Poisons

Some plants accumulate unusually high concentrations of specific minerals found in the soil or in the air. Locoweed (Astragalus mollissimus) is a selenium accumulator. Sufficient ingestion by cattle or horses can cause "blind staggers" and even death. Lethal levels are difficult to consume, however, with horses requiring ingestion of 500 pounds of plants over a six-week period and cattle needing well over 2,000 pounds over a two- to three-month period. Some roadside weeds accumulate lead from exhaust fumes and can produce lead poisoning in animals that feed on them.


This is not actually a category of "poisonous" compounds because, unlike the proceeding, allergens produce a toxic response only to those people (or other animals) who have species sensitivity. The true poisons produce a response in all individuals. Poison ivy (Rhus toxicodendron), shown in Figure 21-11, is easily the most common allergen. Over 100 million people in the United States alone are sensitive to it.


Deadly Plants

The degree of toxicity among poisonous plants varies with the nature of the active compound and with its concentration in the plant. Some plants are only mildly poisonous and others deadly. Table 21-2 includes some of the plants commonly reported to the Poison Control Center in the United States. This list includes most of the highly dangerous plants that one might encounter in the home; several of the most lethal wild and domesticated plants are also included in the following discussion.

Deadly Plants

The degree of toxicity among poisonous plants varies with the nature of the active compound and with its concentration in the plant. Some plants are only mildly poisonous and others deadly. Table 21-2 includes some of the plants commonly reported to the Poison Control Center in the United States. This list includes most of the highly dangerous plants that one might encounter in the home; several of the most lethal wild and domesticated plants are also included in the following discussion.

Hemlock (Conium maculatum, Umbelliferae)

A herbaceous plant with leaves typical of the carrot family, hemlock, shown in Figure 21-12, contains the toxin coniine. It is not the same as the woody hemlock tree. This particular species is recognizable by the reddish purple spots on its stem.


Socrates was poisoned with hemlock in 399 BC for crimes against the state, "neglecting the gods who the city worships" and "corrupting the youth of the city" with his ideas and unwillingness to support the politicians in power. There is evidence that the officials of Athens did not want him to die; they were afraid he would have more support as a martyr than alive. Socrates was given repeated chances to plead guilty and receive a light sentence, but he refused because he had done nothing wrong. He was even given a chance to escape, which he refused. Finally, the sentence was carried out and he was given a cup of hemlock juice to drink, followed by a laudanum of wine, and probably opium to ease the pain of his death.

Socrates insisted on having the stages of the hemlock poisoning accurately observed and recorded. He walked around until his legs began to grow heavy; then he laid down and had someone feel his feet and legs and reported the progression of numbness and cold as it approached his heart. He died of respiratory failure.

Water Hemlock (Cicuta spp., Umbelliferae)

Also a herbaceous plant, water hemlock is found growing in wet habitats such as shallow streams and along the edges of ponds and lakes. Its leaves are not fernlike, as are hemlock leaves; rather, they superficially resemble marijuana leaves. The hollow stems contain a yellow sap, which has the deadly cicutoxin in it. Especially concentrated where the stem and root join, this toxin is even more poisonous than hemlock juice. Death is a painful process involving several convulsions and respiratory failure.

Monkshood (Aconitum napellus, Ranunculaceae)

Also known as wolfbane, this contains the alkaloid aconitine, which is a very powerful poison (see Figure 21-13). Used as an arrow poison by early Stone Age cultures, this toxin is very fast acting; a feature that once also made it a favorite poison.


One of the most famous poisonings accredited to aconitine, is that of the Roman Emperor Claudius, who died suddenly in 54 AD. Historians first blamed Julia Agrippina, Claudius's empress, of doing away with him so that her son by a previous marriage, Nero, could rule. It was later decided that Locusta was the poisoner, working with Stertinus Xenophon, Claudius's personal physician. Locusta also poisoned Britannicus, Claudius's son, so that Nero could rule alone rather than be co-emperor with Britannicus.

Some reports have Claudius poisoned by death angel mushrooms, but the better documented story is that he was fed only small doses of these mushrooms to evoke immediate systems. A feather, previously dipped in aconitine, was used by the physician to tickle his throat to induce vomiting and save Claudius from the attempted mushroom poisoning. That he died anyway was probably accredited to heart failure from the close call, and murder was not officially suspected.

Monkshood is also credited by historians as being the "murder weapon" in the death of Pope Adrian VI and in an unsuccessful attempt on the prophet Mohammed's life. In spite of its well-known toxicity, this plant is attractive and is grown in gardens as an ornamental, especially in Scandinavian countries.

Yew (Taxus spp., Taxaceae)

This plant, shown in Figure 21-14, was prized for the elasticity of the wood and particularly for its value in making the finest of bows. Robin Hood used a yew wood bow because of its qualities. The alkaloid taxine is very poisonous and is found in highest quantities in Japanese and English yew (T. cuspidata and T. baccata). The word toxon means "bow," and toxin means "poisonous." The genus name Taxus is thought to be derived from some combinations of these words.


Oleander (Nerium oleander, Apocynaceae)

Oleander, shown in Figure 21-15, is an extremely poisonous plant. Reported deaths include that of a child who chewed on a single leaf. Unconfirmed reports attest to the danger of eating a hot dog cooked on an oleander stick. Many people value oleander as an attractive landscaping plant without being aware of its danger (or perhaps in spite of it).


Jimsonweed (Datura stramonium, Solanaceae)

Jimsonweed, shown in Figure 21-16, along with many other members of this family, is highly toxic. Also known as thorn apple because of the spiny fruit and moonflower because of its night blooming white flower, the name jimsonweed stems from what occurred in 1676. During Bacon's Rebellion, a group of solders on a march near Jamestown, Virginia, added some Datura leaves to stew. The result was a stupefied regiment that had to be replaced. The "Jamestown Weed" in time became known as jimsonweed.


Tobacco (Nicotiana tabacum, Solanaceae)

Although tobacco, shown in Figure 21-17, is normally listed as a poisonous plant, the presence of the alkaloid nicotine in the leaves qualify it for inclusion in this section. A drop of pure nicotine is toxic enough to kill a medium-size dog in only seconds, and nicotine sulfate is one of the most effective insecticides.


In addition to its toxicity, nicotine is a stimulant and a physiologically and psychologically addictive drug, with physical withdrawal symptoms. In most countries, however, it is legal and is not classified as a narcotic; all other addictive alkaloids are so classified in the United States. Finally, the toxic and addictive drug is known to be a significant contributing factor in a number of respiratory ailments and in throat and lung cancer.

Industrial Plants

Plants provide us with fibers for making cloth, rope, paper, etc. Numerous dyes obtained from plants color our fabrics. Many plants have oil-rich seeds, and these oils can be extracted when they have a variety of uses. Many of them are edible, and they can also be used as lubricants, fuel, for lighting, in paints and varnishes, as a wood preservative, and waterproofing.


The story of natural rubber is one of the most interesting in the history of plant use. The latex sap of many plants contains small amounts of cis-polyisoprene or natural rubber. Only one plant has been a significant source for this material; most of the others simply do not contain enough to be commercially exploitable. A tropical tree native to the Amazon Basin, Hevea brasiliensis, shown in Figure 21-18, is still the only commercial source for natural rubber.


First known in eighteenth century Europe as a bouncy plaything of the Mexican Aztecs and the Amazonian tribes, it received its English name from Joseph Priestly who discovered that this toy would rub out pencil marks. In 1823, a Scotsman named Macintosh discovered that rubber was soluble in naphtha. When such a solution was used to impregnate cloth and the naphtha evaporated away, the result was a waterproof material suitable for protection from the rain. Even today, raincoats are still called mackintoshes in the British Isles.

In 1839, Charles Goodyear accidentally heated raw rubber with some sulfur. The result was a tougher material that would not become tacky in hot weather or stiff and brittle in cold. The process of vulcanization made rubber a much more important product. Vulcanized rubber wears longer, is more resilient, and can be molded into any shape, including that of a tire. Sadly, Goodyear did not establish a patent on this vulcanization process, and it was stolen and patented in France. Charles Goodyear died a pauper after spending the rest of his life trying to be legally credited with the discovery of the vulcanization process.

By the 1800s, raw rubber was in great demand, but Brazil controlled essentially all supplies and forbade the export of rubber tree seeds. After two tries, seeds were finally smuggled out of Brazil for the Royal Botanical Garden of England, and seedlings were successfully transported to the British protectorate Ceylon (Sir Lanka) Asian Hevea plantations have taken over as the primary supplies of rubber for the past century. Brazil never became sophisticated enough industrially to maintain early dominance.

Natural rubber shortages during World War II prompted the development of synthetic rubber, but it does not have all the properties of natural rubber. Many rubber products, including radial tires, required natural rubber. Since many of these items are being sold in increasing amounts, it is feasible that another rubber shortage could occur unless a new source can be developed for commercial rubber production.


Oils and Waxes

Oils contained in fruits, seeds, and other plant parts fall into several categories based on their chemical composition and use. Cooking oils, soaps, plastic, paints, linoleum, lubricants, and printing inks are a few examples of the range of plant oil users. Tung, caster, olive, palm, coconut, soybean, peanut, cottonseed, linseed, sunflower, safflower, canola, and corn oils are some plant oils with a wide variety of commercial uses. Oils are often divided into three categories according to their qualities, these categories are nondrying, semidrying, and drying. Nondrying oils are slow to oxidize and so remain liquid for a long time. This quality makes them particularly useful as lubricants and as a fuel for lamps. Drying oils, on the other hand, are quite quick to oxidize and become solid, thus, they are often used in paints and varnishes. Linseed oil is a good example of this. Semidrying oils have qualities intermediate between the other two groups. Almost all commercially grown oil seed crops in the temperate zone are of annual plants. The list is quite long of plants that are used in industry, but some of the most common ones are rape (see Figure 21-19), soya, linseed, sunflower, and safflower.

Waxes from plants play a fairly minor role in the world's economy, but several are important. Used in candles, textile sizing, and leather treatments and coatings, vegetable waxes yield to animal, mineral, and synthetic sources in economic importance. The most significant vegetable oil is undoubtedly carnauba wax, from a palm tree native to northeastern Brazil (Copernicia cerifera). One of the finest automobile waxes, carnauba, is also used in the manufacture of lubricants, chalk, matches, plastics, film, cosmetics, and as an additive to other waxes. It is the hardest natural wax and has the highest melting points of any known wax. Candelilla wax comes from the Euphorbia antisyphilitica, which grows in the desert areas of northern Mexico. Extracted in small quantities from wild plants, this wax is very similar to carnauba wax in most of its properties. In spite of being a high-quality wax, it will probably never become a cultivated plant producing a large annual yield because of its preferred habitat. It is used primarily for candle production.


Cotton (Gossypium hirsutum) is probably the most widely used plant fiber. Cotton was first popularized as a replacement for wool in Europe during the Dark Ages. Wool garments harbored disease-carrying lice and fleas, could not be washed expediently, and were scratchy for summer wear. Cotton was soft, washable, reasonably durable, and, once available commercially, inexpensive. Cotton fibers are not like the fiber cells found in stems; rather they are elongated seed epidermal cells (see Figure 21-20).


Another fiber producing plant is flax (Linum), from which linen, paper money, and cigarette paper are made from. Popular in ancient Egypt, fine linen was even used for wrapping mummies. Sisal is a coarse fiber from the leaves of the Agave and is primarily made into binding twine. Hemp fibers from Cannabis stems are excellent for canvas and hemp rope, but hemp is not commercially produced in the United States.


1. The early history of plants was the history of herbalism and medicinal plants. Modern medicine includes little "traditional medicine" in the Western world but a balanced approach in China. Some of the more primitive societies in Africa and South America also depend extensively on their medicine men even today.

2. Medical plants were often surrounded by mysticism and superstition even though many of them contained compounds that did affect the body physiologically. Some of the well-documented medical plants include mandrake, Duboisia, and belladonna, all in the Solanaceae. In addition, Cinchona, Opium poppy, curare, Rauwolfia, Ephedra, foxglove, ergot, senna, St. John's Wort, Gingko biloba, and cascara have medicinal properties.

3. Many herbal remedies have less dependable curative powers, but many people still depend on these plants for general well-being, minor pain relief, topical cuts and burns, internal organ disorders, and respiratory tract disorders.

4. Psychoactive plants include such stimulants as cocaine, depressants such as the opiates, the true hallucinogens such as marijuana, ergot, fly agaric, sacred mushrooms, peyote, and members of the Solanaceae.

5. Poisonous plants contain active ingredients in one of several classes of compounds. Internal organ poisons include the alkaloids and cardiac and cyanogenic glycosides. Also producing toxicity in the internal organs are plants containing oxalates, resins, and phytotoxins.

6. There are about 75 species of fungus that are poisonous and about 10 that are deadly. Members of the genus Amanita are among the most toxic of all mushrooms.

7. The deadly toxic plants include hemlock and water hemlock, monkshood, yew, oleander, jimsonweed, and tobacco. Many others are only slightly toxic.

8. Plants with industrial importance include the latex producers, such as Hevea, those that contain oils, and fiber-containing plants, such as cotton, flax, hemp, and sisal.

Something to Think About

1. Where are medicine men still being used?

2. List some of the well-documented medicinal plants.

3. How do people still use herbal medicines?

4. List the psychoactive plants.

5. Name ingredients of poisonous plants.

Suggested Readings

Bresinsky, A. and H. Besl. 1990. A colour atlas of poisonous fungi. New York: Wiley.

Ellis, D. 2003. Medicinal herbs and poisonous plants. London: Blackie and Son.

Gottlieb, A. 1997. Peyote and other psychoactive cacti (2nd ed.). Berkeley, CA: Ronin Publishing.

Gruber, H. 1992. Growing the hallucinogens : How to cultivate and harvest legal psychoactive plants (3rd ed.). Berkeley, CA: Ronin Publishing.

Schultes, R. E., et al. 2001. Plants of the gods: Their sacred healing and hallucinogenic powers. Rochester, VT: Healing Arts Press.


Internet sites represent a vast resource of information. The URLs for Web sites can change. Using one of the search engines on the Internet, such as Google, Yahoo!,, and MSN Live Search, find more information by searching for these words or phrases: herbalism, medicinal plants, codeine, heroin, morphine, Opium Wars, hallucinogenic plants, poisonous compounds from plants, and industrial plants.
Table 21-1
Selected Herbal Remedy Plants of the United States

Plant                       Plant part used

Aloe (Aloe vera)            Leaves, mucilaginous juice

Alum (Hechera spp.)         Root, chopped, 1 teaspoon
                            boiled for 20 minutes

Asparagus (Asparagus        Root chopped and steeped in
officinalis)                boiling water to make a tea

Birch (Betula)              Bark

Catnip (Nepeta cataria)     Entire plant

Comfrey (Symphytum          Root extraction in water

Dandelion (Taraxacum        Leaves and flowers, steeped in
officinalis)                boiling water to make a tea

Dogbane (Apocynum           Roots

Gentian (Gentian spp.)      Roots; chopped and steeped in
                            hot water for 30 minutes

Mullein (Verbascum          Large, basal leaves; washed
thapsus)                    dried, chopped, steeped in

Oak (Quercus spp.)          Bark or small twigs; chopped
                            and steeped in water to make
                            a tea

Old man's beard             Branches; chopped and steeped
(Clematis spp.)             in boiling water to make tea

Plantain (Plantago          Fresh leaves

Pleurisy root               Poultices; chopped and boiled
(Asclepias tuberosa)        in water

Willow (Salix spp.)         Twigs or bark; boiled in water
                            for 2 hours

Plant                       Purported value

Aloe (Aloe vera)            A tropical pain reliever,
                            promoting healing of burns and

Alum (Hechera spp.)         An astringent for treatment of
                            stomach flu, ulcers, sore throat
                            (gargle), and cuts and abrasions
                            (promotes clotting)

Asparagus (Asparagus        A diuretic and laxative for
officinalis)                treatment of gout and related
                            joint inflammations; helps
                            prevent kidney stones

Birch (Betula)              An analgesic for headaches and
                            arthritis; methyl salicylate
                            active ingredient

Catnip (Nepeta cataria)     A mild tranquilizer, treatment
                            for colic or teething in young

Comfrey (Symphytum          Mucilage acts as a demulcent and
officinale)                 tonic for the respiratory tract;
                            also used as a stomach tonic and
                            to sooth diarrhea and dysentery;
                            may be toxic

Dandelion (Taraxacum        Diuretic; treatment for kidney
officinalis)                inflammations; as an aid to
                            liver and spleen functions

Dogbane (Apocynum           Cardiac stimulant may be toxic

Gentian (Gentian spp.)      Considered an excellent stomach
                            tonic for indigestion,
                            heartburn, etc.

Mullein (Verbascum          Throat, chest, and lung maladies
thapsus)                    such as coughing, asthma, and
                            respiratory tract infections

Oak (Quercus spp.)          As astringent for gum
                            inflammations, sore throat
                            gargle, intestinal tonic

Old man's beard             Treatment of headaches,
(Clematis spp.)             especially migraine; dilates
                            veins but has a vasconstricting
                            effect on the brain lining

Plantain (Plantago          Poultice; treatment for insect
major)                      bites and skin abrasions; also
                            useful for mild intestinal
                            inflammations and hemorrhoids

Pleurisy root               Increases perspiration and
(Asclepias tuberosa)        bronchial dilation; treatment
                            for pleurisy edema; may be toxic

Willow (Salix spp.)         General analgesic action;
                            reduces inflammation of joints
                            and membranes, eases headaches,
                            lowers fevers, and reduces neuralgia;
                            antiseptic wash or poultice for
                            skin abrasions, eczema, or infected

Table 21-2
Common Poisonous House and Yard Plants

                   Scientific name      Poisonous
Common name        (family)             parts

                              House plants

Castor beans       Ricinus communis     Seeds must be
Rosary pea         (Euphorbiaceae)      chewed

Mistletoe          Phoradendron         All parts; espe-
                   (Loranthaceae)       cially berries

Dumb cane          Dieffenbachia        All parts

Caladium           Caladium             All parts in-
                   (Araceae)            cluding tuber

Elephant's         Colocasia            All parts
ear                antiquorum

Philodendrons      Philodendron and     All parts

Crotons            Croton               Seeds, leaves
                   (Euphorbiaceae)      and stems

Crown of thorns    Euphorbia milii      All parts

                        Yard and garden plants

Daffodil           Narcissus            Bulbs

Autumn crocus      Colchicum            Bulbs, flowers
                   autumnale            and seeds

Star of            Ornithogalum         All parts
Bethlehem          umbellatum           including bulbs

Pokeweed,          Phytolacca           Roots, shoots,
poke berries       Americana            berries

Iris               Iris spp.            Leaves and
                   (Iridaceae)          rhizomes

Yew (English       Taxus spp.           Bark, leaves, and
and Japanese       (Taxaceae)           seeds

Oleander           Nerium oleander      All parts

Daphne             Daphne mezereum      Berries

Rhododendron       Rhododendron spp.    All parts
laurel, azalea     (Ericaceae)

Buckeye, horse     Aesculus hippocas-   Leaves, flowers,
chestnut           tanum (Hippoca-      young sprouts,
                   stanaceae)           seeds, pods

Wisteria           Wisteria spp.        Seeds, pods

Jimsonweed,        Datura stramonium    All parts espe-
thorn apple        (Solanaceae)         cially the seeds

Woody              Solanum nigrum       Leaves, roots,
nightshade,        (Solanaceae)         berries
bitter sweet

Irish potato       Solanum tuberosum    When tubers are
                   (Solanaceae)         exposed to light,
                                        the green tissue
                                        under the skin

Jerusalem          Solanum pseudocarp   Berries
cherry             (Solanaceae)

Elderberry         Sambucus spp.        Stem, leaves,
                   (Caprifoliaceae)     unripe berries

Holly              Ilex spp.            Berries

English ivy        Hedera helix         Leaves, berries

Foxglove           Digitalis purpurea   Leaves, seeds,
                   (Scrophulariaceae)   flowers

Lily of the        Corvallaria          Roots, leaves,
valley             majalis              flowers and fruits

Monkshood          Aconitum spp.        All parts
                   (Ranunculaceae)      especially roots
                                        and leaves

Rhubarb            Rheum rhaponticum    Leaves (not
                   (Polygonaceae)       petioles, which
                                        are edible)

Common name        compound             Symptoms

                                  House plants

Castor beans       Ricin and lectin     Nausea, muscle spasms,
Rosary pea                              purgation convulsions, and
                                        death; lethal dose 8 seeds

Mistletoe          Toxic amines;        Stomach upset and in severe
                   protein              cases death from inability to

Dumb cane          Calcium oxalate      Burning sensation in mouth and
                   and proteolytic      swelling of mouth and throat
                   enzymes;             tissue could lead to
                   asparagine           asphyxiation in small children

Caladium           Calcium oxalate      Burning sensation in mouth
                   and/or irritant      and swelling of mouth and
                   juices; asparagine   throat tissue could lead to
                                        asphyxiation in small children

Elephant's         Calcium oxalate      Burning sensation in mouth
ear                and/or irritant      and swelling of mouth and
                   juices; asparagine   throat tissue could lead to
                                        asphyxiation in small children

Philodendrons      Calcium oxalate      Burning sensation in mouth
                   and/or irritant      and swelling of mouth and
                   juices; asparagine   throat tissue could lead to
                                        asphyxiation in small children

Crotons            Croton oil           Powerful purgative action
                                        that can cause death on
                                        ingestion of small amounts

Crown of thorns    Milky sap contains   Can cause severe irritation
                   acrid irritant       if ingested in large
                                        quantities as complex esters

                            Yard and garden plants

Daffodil           Calcium oxalate      Nausea, vomiting, diarrhea;
                   crystals             if eaten in quantity, could
                                        be fatal

Autumn crocus      Colchicine and       Burning in the throat and
                   other alkaloids      stomach vomiting; weak, quick
                                        pulse; kidney failure;
                                        respiratory failure

Star of            Cardiac              Nausea, gastroenteritis
Bethlehem          glycosides

Pokeweed,          Triterpenesaponin,   Severe gastrointestinal
poke berries       lectin, mitogen      disturbance weakened pulse
                                        and respiration; can be fatal

Iris               A glycoside          Gastrointestinal disturbance,
                                        sometimes a burning in the

Yew (English       Alkaloid, taxine     Fatal; taxine readily
and Japanese                            absorbed in intestines; death
                                        is sudden

Oleander           Cardiac glycosides   Severe vomiting, bloody
                                        diarrhea,irregular heartbeat,
                                        drowsiness, unconsciousness,
                                        respiratory paralysis, and

Daphne             Coumarin             Fatal! a few berries can kill
                   glycoside, and a     a child; burning of the
                   diterpene,           throat and stomach, internal
                                        bleeding, coma, and death

Rhododendron       mezereon Resin       Vomiting, weakness, and in
laurel, azalea                          extreme cases paralysis and

Buckeye, horse     Lactone glycoside,   Vomiting, diarrhea, lack of
chestnut           esculin              coordination, paralysis,
                                        (used extracts of buckeye for
                                        fish poison)

Wisteria           Lectin, mitogens     Mild to severe digestive upset

Jimsonweed,        Scopolamine          Flushed skin, dilated pupils,
thorn apple        hyoscyamine,         dry mouth, delirium, and
                   alkaloids            death due to respiratory

Woody              Solanine alkamine    Burning in the throat,
nightshade,        aglycones            nausea, dizziness, dilated
bitter sweet                            pupils, weak convulsions; can
                                        be fatal

Irish potato       Solanine alkamine    Burning in the throat,
                   aglycones            nausea, dizziness, dilated
                                        pupils, weak convulsions; can
                                        be fatal

Jerusalem          Solanine alkamine    Burning in the throat, nausea,
cherry             aglycones            dizziness, dilated pupils,
                                        weak convulsions; can be fatal

Elderberry         Alkaloids,           Burning in the mouth, throat,
                   cyanogenic           and stomach

Holly              Toxic compound       Not fatal, but purgative and
                   unknown              emetic and most dangerous to

English ivy        Triterpene           Vomiting, diarrhea, and
                   sapogenin,           nervous depression; can be
                   hederagenin          serious in small children

Foxglove           Digitoxin, cardiac   Large amount can cause
                   glycosides           dangerously irregular
                                        heartbeat, mental confusion,
                                        and digestive upset; usually

Lily of the        Cardiac glycoside,   Large amounts cause
valley             convalla toxin       dangerously irregular
                                        heartbeat, mental confusion,
                                        and digestive upset; usually

Monkshood          Aconitine            Numbness, paralysis of upper
                   (alkaloid)           then lower extremities; death
                                        by respiratory paralysis;
                                        very poisonous

Rhubarb            Oxalates,            Stomach pain, nausea, vomiting
                   anthraquinone        and in serious cases
                   glycosides           convulsions, internal
                                        bleeding, coma, and death;
                                        very poisonous
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Publication:Fundamentals of Plant Science
Date:Jan 1, 2009
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