Alternative medicine: herbal drugs and their critical appraisal--part II.

The availability of herbal products as "over-the-counter" drugs and their increasing usage in the US and Canada have caused concern at the US FDA, since these products are not currently monitored for their safety, efficacy and quality. Reliable information on these aspects of the products is not available. Most of the clinical trials carried out to date have been lacking in scientific design, data collection and interpretation, and systematic toxicological evaluation. A critical review of the existing data on three of the widely used herbs and their products is presented. Of the three herbs, garlic and ginger, through both experimental and clinical data, as well as their liberal consumption by man over millennia, appear to be very safe for therapeutic use. However, further and large-scale, well-designed clinical investigations are needed to establish their efficacy before they can enter the mainstream drug market of North America. It is hoped that this review will equip the physicians and interested biomedical scientists with a comprehensive summary of the total information available to date on the herbs described.