Alternative medicine: what the data say about common herbal therapies.

An increasing number of Americans are turning to complementary and alternative medicine to help manage or prevent the onset of chronic disease, improve cognitive function, boost overall general well-being, and increase longevity. Some of the more widely-used herbal preparations designed to help accomplish these objectives include St. John's wort, ginkgo biloba, echinacea, garlic, and ginger. In general, the clinical trial data on these preparations is in the embryonic stages, whereas the popularity of these compounds is fueled in part by anecdotal evidence. Given the embrace by Americans--especially older persons--of these alternative remedies, knowledge of their uses and potential side effects can help the primary care physician better collaborate on a course of care that makes effective use of the best treatments, both traditional and alternative.