Herbal medicines: where is the evidence?
With the market for herbal supplements now approaching $4bn a year in the United States alone, what evidence is there to show that these treatments actually work, asks Professor Ernst of Exeter University's Department of Complimentary Medicine in a BMJ editorial this week.
An increasing body of evidence is now emerging that suggest some herbal medicines are effective -- and often have fewer adverse effects than standard treatments, says the author. For instance, more than 30 clinical trials show St John's Wort to be as effective as conventional antidepressants and ginkgo biloba has been shown to be more effective than placebo in delaying the clinical course of dementia.
Despite these positive results, we should be aware of the risks, warns the author. We do not fully understand how many of these medicines work and, as many herbal remedies are sold as food supplements, they evade the quality and safety regulations required for conventional treatments. Two recent cases of severe kidney damage caused by Chinese herbal tea taken to treat eczema illustrate the need for a quality standard for all herbal preparations. Potential herb-drug interactions and the cost-effectiveness of herbal medicines must also be explored, suggests the author
As more people turn towards herbal medicines, health professionals need access to reliable information in order to advise their patients responsibly, concludes the author. The UK's minister for public health recently called for better protection and information for the public on herbal medicines and doctors should take an active part in this process, he adds.
Contact:
Professor E Ernst, Department of Complimentary Medicine, School of Postgraduate Medicine and Health Sciences, University of Exeter, UK
Email: E.Ernst@exeter.ac.uk