Richard Ondrizek, MD and colleagues found three of the four herbs examined echinacea, purpura, gingko biloba and St. John?s wort inhibited sperm penetration in a study using hamsters. The experiments showed that St. John?s wort also causes mutations on the BRCA1 gene, which has been linked to breast and ovarian cancer. A mild mood elevator, St. John?s wort has become enormously popular as an herbal remedy for mild to moderate depression.

Besides having particular note for infertile couples, the study results are also news for the thousands of men who use saw palmetto for benign prostatic hyperplasia (enlarged prostate). Saw palmetto was the only one of the four herbs studied that did not affect fertility or cause DNA damage.

There are no FDA guidelines for daily allowances of herbs, and FDA regulations prohibit herbs from claiming disease-specific remedies. The American Medical Association (AMA) guidelines say pregnant and lactating women should avoid herbs. The herbs studied are leaders in the supplement industry, whose growth is partly due to a perception that they are natural and "safe," and do not pose risks to vital functions. Echinacea, the top-selling herb, is said to stimulate the immune system, and ginkgo biloba is widely used to improve memory.

Because of the lack of medical standards for herbs, the study points to the need for further study, including the gene changes.

"Any change in BRCA1 is a concern regardless of effect," said Dr. Ondrizek, lead author of the study. "Further studies, such as sequencing of the mutated gene, should confirm the type of damage caused to the sperm cell by St. John?s wort," the researchers wrote.

The study showed St. John?s wort had the strongest effect on sperm penetration, and both St. John?s wort and echinacea caused DNA denaturation (or damage) and a reduction in sperm viability.

Incubation of sperm with St. John?s wort caused a specific point mutation in the BRCA1 exon 1 gene. Further study is needed to identify the active components of St. John?s wort responsible for cellular damage.

Saw palmetto did not cause DNA denaturation and also did not cause inhibit sperm penetration in the experiments. No data exists, according to the authors, on concentrations of the herbs in semen or serum. High concentrations of the three herbs showed the adverse effects on sperm penetration of eggs at high concentrations, but at lower concentrations the penetration was comparable to the control group.

"The possible lack of a physiologic effect in vivo should be considered," the researcher said.

The study raises important questions, but that the applicability to humans may be very different. Clinically, she said, animals, humans and in-vitro may be very different. "Until you have human data, you have to be careful," said Carolyn D. Runowicz, MD, professor and director of the division of gynecologic oncology, department of obstetrics, gynecology and women?s health, Albert Einstein College of Medicine, Montefiore Medical Center, New York.

"Animal data is not relevant to human data." Referring to the study?s finding on the effect on the BRCA1 gene, she added, "As far as the gene mutation, it needs further study. It is very provocative and a reason to study these products and mutations."

The study also points up the need for patients to inform their doctors about their use of herbs, she said, because it shows there can be harmful as well as beneficial effects from products that are considered "natural."

Dr. Dorothy Mitchell-Leef, a practicing fertility specialist with Reproductive Biology Associates in Atlanta, agreed saying, herbs and other supplements that her patients may use are a concern because of the lack of information on their effects. Complicating their usage, she added, is that patients do not always tell doctors that they are taking them.

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