Some herbals may threaten fertility.

Herbal remedies are hot. Concerned because many of his patients with infertility problems admitted to using these products, Richard R. Ondrizek decided to investigate their potential to affect reproduction. His research team at Loma Linda (Calif.) University School of Medicine now reports that some of the more popular botanical therapies appear capable of inhibiting conception or damaging sperm.

The scientists began by incubating hamster eggs for an hour with preparations of echinacea, saw palmetto (Serenoa repens), ginkgo biloba, or St. John's wort (Hypericum perforatum). The saw palmetto had no effect, but high concentrations of the others impaired human sperm's ability to penetrate the eggs. In the absence of any herbal remedy, the sperm penetrated 63 to 88 percent of the eggs. That proportion dropped to 13 percent in the eggs incubated with echinacea and to 0 in those exposed to ginkgo or St. John's wort, Ondrizek's group reports in the March Fertility and Sterility.

In a second set of experiments, the researchers bathed sperm for 1 week with dilute solutions of the herbal preparations. Echinacea and St. John's wort damaged the sperm's outer membrane. St. John's wort also produced mutations within the sperm in BRCA1, a gene in which mutations have been linked to breast cancer.

Ondrizek cautions that his tests were preliminary but says his findings--especially those documenting mutations--"warrant some attention." Certainly, he explains, "if something is able to change BRCA1, you have to assume that it has the ability to change DNA," perhaps even leading to cancer.