SINCE 1999 the National Institutes of Health has spent more than $2.2 billion testing the benefits and risks of alternative medicine, funding studies on everything from shark cartilage (a bunk therapy for lung cancer, evidently) to meditation (which has been shown to improve brain function). Much of that money flows through the NIH’s alternative medicine clearinghouse, the National Center for Complementary and Alternative Medicine (NCCAM).

The results have been decidedly mixed. Consider St John’s Wort, which took off in the 1990s as a “natural” way to treat depression. In a widely reported 2002 study, an international team of researchers discovered that the herb actually has no impact on severe depression—though studies continue to assess its impact on low-level depression and a range of other ailments.

And while a 2004 trial found that acupuncture offers pain relief and improved mobility for people suffering from osteoarthritis of the knee, a degenerative joint disease that affects more than 10 million Americans, other acupuncture claims—e.g., that it can ameliorate fibromyalgia—have yet to be substantiated.

Part of the problem has to do with basic incompatibilities between alternative medicine and Western science. It’s difficult for a lab to test the efficacy of herbal supplements that, due to scant federal regulation, are sold in all manner of forms and purity levels. And it’s essentially impossible to evaluate alternative remedies that claim to cure health conditions—such as insufficient pitta—that don’t even exist in Western medicine.

While you can stay informed about new developments by visiting NCCAM’s information-packed website (www.nccam.nih.gov) or by (warily) perusing consumer magazines such as Alternative Medicine, which reports on recent health studies—and plugs the latest natural fads—few people have time for that. Which means that ultimately, the simplest way to get your questions answered is to consult your own doctor or health insurance plan.

At Kaiser Permanente, for instance, a committee of physicians routinely vets the literature to set coverage policies. Their recommendations indicate, among other things, that acupuncture can help morning sickness and that naturopathic medicine can improve conditions such as atopic dermatitis. Some of Kaiser’s pharmacies even stock botanical supplements, such as gingko biloba for memory loss.

And if all of your unanswered questions keep you up at night? Try taking some melatonin—which some studies indicate should help you fall asleep.