These guidelines for the clinical evaluation of herbal medicines attempt to recognize the long and diverse history of traditional medicine in the Region and the differences between the diagnostic systems of modern medicine and the various traditional medicines of the Member States. Although special considerations may be required, the general principles of the clinical trials of herbal medicines are similar to those applied to synthetic drugs if clinical trial is regarded to be necessary.

Clinical trials of herbal medicines may have two types of objectives. One is to validate the safety and efficacy that is claimed for a traditional herbal medicine. The other is to develop new herbal medicines or examine a new indication for an existing herbal. medicine or a change of dose formulation, or route of administration. In some cases, trials may be designed to test the clinical activity of a purified or semi-purified compound derived from herbal medicines.