Medicinal herbs: drugs or dietary supplements?

The process of evaluating medicinal herbs is complex, and there is a need to carefully define a research strategy that addresses a solution to safe and efficacious herbal products. Notwithstanding the immense value of distilling the pharmacological activity of an herb into a chemical suitable for drug development, another approach is to develop a standardized herbal extract that yields consistent pharmacological activity. However, it frequently is forgotten that even in an extract several active ingredients contribute to the pharmacological action. Sufficient evidence exists to suggest that extracts of medicinal herbs, once isolated in their pure state, can produce pharmacological effects that differ significantly from that of the whole herb. This article discusses a research-based strategy that may be suitable for validating, in part, the putative health benefits of medicinal herbs. Additionally, the body of scientific evidence that underpins the pharmacological activity of several herbs is reviewed briefly.