Monitoring the safety of herbal medicines.

Extremely limited knowledge about the ingredients in herbal medicines and their effects in humans, the lack of stringent quality control and the heterogenous nature of herbal medicines all necessitate the continuous monitoring of the safety of these products. In Hong Kong, safety information on herbal medicines has come from the enquiries and reports received by our Drug and Poisons Information Service, on-going surveillance of patients treated in a large general teaching hospital and review of reports from the medical literature. Circumstances under which poisonings have occurred are also analysed in order to devise preventive measures. Once collected, this information is then distributed to health professionals in Hong Kong and abroad. WHO projects and pilot studies in Europe are also under way to promote and facilitate reporting of adverse reactions to herbal medicines.