Assessing the risks and benefits of herbal medicine: an overview of scientific evidence.

The use of herbal medicine is widespread and growing, with as many as 3 in 10 Americans using botanical remedies in a given year. Because many herbal medicines have significant pharmacological activity, and thus potential adverse effects and drug interactions, healthcare professionals must be familiar with this therapeutic modality. This article summarizes the history and current use of plant-based medicine and highlights the evidence of the risks and benefits associated with 6 plants: echinacea, garlic, ginger, ginkgo, St John's wort, and valerian. Therapies outside the medical mainstream tend to suffer from a dearth of research and critical evaluation. Critics and supporters alike note the conceptual and practical difficulties in studying many complementary and alternative therapies such as acupuncture, homeopathy, and meditation. Herbal medicine, however, lends itself well to standard evaluation methods. This article summarizes and evaluates evidence from randomized controlled trials and meta-analyses. We present the results of meta-analyses and subsequent randomized controlled trials for garlic and St John's wort; a comprehensive critical review and subsequent randomized controlled trials for ginkgo; and summaries of all identified randomized controlled trials for echinacea, ginger, and valerian.

Complementary and alternative medicine: what's it all about?

A number of health-related interventions--from widespread therapies such as acupuncture, herbal medicine, homeopathy and yoga, to less well-known modalities such as Feldenkrais, iridology, reflexology and reiki--have increasingly come under the general heading of complementary and alternative medicine (CAM). A few, such as biofeedback, chiropractic and physical therapy, are considered conventional by some, alternative by others. Several national surveys estimate that around 40% of the US populace uses a CAM therapy in a given year. While a few people use CAM therapies instead of conventional medicine, the vast majority of CAM users continue to access the official health care system. Many, however, do not discuss their CAM use with their physician. Medical doctors, for their part, are sharply divided on their attitudes toward CAM, with strong advocates and vehement opponents writing and speaking about this issue. CAM therapists are even more diverse, spanning the spectrum from conventional-appearing registered and certified practitioners to iconoclasts promoting anomalous therapies in the place of conventional treatment. The majority, however, both respect and want to work with conventional medicine, as do their patients. Nearly everyone is calling for more and better evidence, and an ever-increasing number of randomized controlled trials and meta-analyses are now appearing in the literature. Over the past few years, a number of calls for "integrated medicine" have been made, and a few attempts at integrating CAM and conventional medicine have been launched. This article reviews these issues, citing our own interview-based work and the relevant literature. Whether the CAM phenomenon represents a short-lived social movement or the beginnings of a radical transformation of medicine has yet to be determined.