Plant medicines gain some peer-reviewed respect
Because much of the research concerning herbal medicines is published in languages other than English, most North American physicians have heard little about the scientific evidence outlining the therapeutic efficacy of these products. "But," says Dr. Edzard Ernst, chair of the Department of Complementary Medicine at the Postgraduate Medical School, University of Exeter, "randomized, double-blind, placebo-controlled clinical trials for herbal remedies exist, and these are the data we should accept."
Some of the evidence is now finding its way into respected, world-class journals. Last year JAMA reported that Ginkgo biloba, which is widely used in Germany to treat dementia-type syndromes and symptoms of forgetfulness and poor concentration, had led to improvement in patients with Alzheimer's disease (JAMA 1997;278:1327-32). The study determined that patients showed clinically meaningful improvement in cognitive functioning after taking the product for a year. The study is considered one of the first to evaluate a herbal remedy scientifically.
St. John's wort has also received significant scientific scrutiny. According to a meta-analysis of 15 placebo-controlled trials published in the BMJ, patients with mild to moderate depression taking this herbal remedy were 2.7 times more likely to improve relative to placebo (BMJ 1996;313:253-4). Symptoms typically improve after 2 to 4 weeks of treatment, and there are no sedating side effects. Improvements in sleep disturbances have also been shown to accompany improvements in mood.
Garlic, which has also been touted for its beneficial effects on the cardiovascular system, received peer-reviewed support last year when Circulation reported that "data strongly support the hypothesis that garlic intake had a protective effect on the elastic properties of the aorta related to aging in humans" (Circulation 1997;96:2649-55). It was the first study involving phytomedicine to appear in that journal.
