Nicotine - chewing on it.

During the past few months, events have focused a spotlight on the nicotine in cigarettes (see p.314). But this potentially addictive drug naturally laces smokeless tobaccos, too. Moreover, unlike cigarettes, snuff and chewing tobacco labels do not disclose the amount of nicotine these products contain.

Arguing that consumers have a right to such information, three researchers with the University of Alabama at Birmingham have just analyzed and published for the first time the nicotine content -- by brand -- of 11 of these smokeless products.

They include the most popular moist snuffs as well as loose-leaf chewing and "plug" tobaccos.

From a health perspective, nicotine intake is important because "it drives tobacco usage patterns," says oral pathologist Brad Rodu, who headed the study. And research has linked smokeless tobacco not only to leukoplakia -- oral callouses--but also to the development of oral cancers.

Five of the six analyzed snuffs led the list -- carrying between 2.1 and 3.35 percent nicotine by weight. Manufacturers tend to sweeten chewing tobaccos with sugar, which can dilute their nicotine content, notes Rodu. Indeed, the two plug tobaccos weighed in with a little more than 1.6 percent nicotine each; the three loose-leaf products had 0.77 to 1.1 percent.

Ironically, the product with the least amount of nicotine was a moist snuff: Conwood Co.'s Hawken brand possessed just 0.59 percent of the drug by weight, the Birmingham team reports in the May JOURNAL OF THE AMERICAN DENTAL ASSOCIATION.

Studies show that smokeless-tobacco users subconsciously modulate how they use these products -- such as by holding one wad in the cheek for 4 hours instead of replacing it every 30 minutes -- to achieve a relatively constant concentration of nicotine in the blood. In fact, Rodu notes, these tobacco users often obtain as much nicotine from their "habit" as do cigarette smokers.