Do you reach for echinacea instead of NyQuil when you get the sniffles? Have you been taking ginkgo biloba faithfully to keep your memory sharp? Do you think St. John's Wort can alleviate your depression as well as Zoloft or Paxil can?

If so, you're among the millions of Americans who use natural and herbal products for health reasons. In 2002, nearly one in five American adults bought natural supplements to treat everything from arthritis and anxiety to hypertension, menopause and insomnia.

But for some natural products, medical claims are based more on folklore than fact. And unlike drugs sold by prescription or over the counter, natural and herbal supplements can be sold without any proof of safety or effectiveness. The U.S. Food and Drug Administration (FDA), which regulates dietary supplements, does not verify what's actually in them. It can take action only after an unsafe product reaches the market.

Results of testing by other agencies sometimes give pause. For example, the National Center for Complementary and Alternative Medicine, an arm of the National Institutes of Health, funded a 2001 study that found most ginseng supplements contained less than half the potency advertised. And a 2003 study in the Archives of Internal Medicine reported that about half the 59 echinacea products analyzed did not contain the species listed on the label.

"With the lack of regulation and standardization, how can a patient be sure that the gingko biloba on a store shelf even contains ginkgo at all, much less in what dosage?" asks Dr. Jonathan LaPook, an internist and gastroenterologist at Columbia University Medical Center in New York.

Yet even when supplements contain what the labels say they do, and even when they are taken in the recommended dose, they might not deliver the desired medical benefit. Many herbal and natural supplements haven't been tested through rigorous clinical trials to measure their effectiveness.

For instance, a mini physician's guide to herbs and supplements published by the University of Washington's Department of Family Medicine notes that such popular products as milk thistle, chamomile and feverfew lack significant data to back up their purported health benefits.

One instance where rigorous testing made news was last month when the New England Journal of Medicine published the results of a large federally funded study that found echinacea, the top-selling herbal medicine in the U.S., was no more effective in preventing and treating colds than a placebo.

The study's authors concluded that numerous previous studies failed to demonstrate echinacea's effectiveness — and that the herb should be considered an ineffective remedy for colds until proven otherwise.

A history of herbal use

Herbs have been used for medicinal purposes for thousands of years — far longer than conventional drugs — and generally they have good safety records, said LaPook, co-author of The Columbia University College of Physicians & Surgeons Complete Home Medical Guide (Crown Publishers, 1995).

Lack of rigorous testing doesn't necessarily mean herbal remedies are ineffective or unsafe, but that they haven't been proved otherwise.

Some herbal remedies mature to become recognized in the world of conventional medicine. Aspirin, after all, was derived from a compound in willow bark, and digitalis, a key ingredient in drugs that control heart rate, was derived from the foxglove plant.

More and more American physicians are incorporating alternative therapies into their practices. LaPook said he often recommends ginger for patients with nausea.

But dangers can arise when patients don't tell their doctors they're taking herbs and supplements. Ginger and garlic, for instance, can interfere with blood clotting. That's why, to prevent excessive bleeding, LaPook orders patients to stop all herbs and supplements before he performs a colonoscopy.

A 1993 study published in the New England Journal of Medicine found that a third of Americans used unconventional therapy in the previous year, but 72 percent of them did not tell their medical doctor they were doing so.

"It is crucial to remember that herbs are medicine and therefore can have side effects," LaPook said.

Supplement cautions

Even practitioners of alternative medicine, though they prescribe herbal remedies, recommend consumers seek professional advice before taking them.

Kathie Golden, a naturopathic doctor at Bastyr Center for Natural Health in Wallingford, a teaching clinic for Bastyr University, said botanical or natural products can be a gentler alternative to conventional drugs. For example, Golden said, patients who take goldenseal, an herb with antiseptic properties, might avoid upset stomach and other side effects associated with antibiotics.

Golden said she conducts quality reviews for products sold at Bastyr's dispensary in Wallingford. Consumers elsewhere may want to check for one of several independent "seals of approval" for supplement quality. One such stamp, called the Good Manufacturing Practices seal, is issued by The National Nutritional Foods Association, a trade group, for products that meet standards for truth in labeling and ingredient quality.

Medical experts say pregnant and nursing women, children, the elderly and patients undergoing surgery should be extremely careful about taking herbal or natural products or shouldn't take them at all.

Golden recommends that patients interested in supplements consult naturopaths, who receive formal training in nutrition and botanical medicine that most conventional physicians lack.

"A person shouldn't be making decisions about what dose (of herbal supplements) to take any more than they should decide what dose of penicillin to take," Golden said.

Kyung Song: 206-464-2423 or ksong@seattletimes.com