Side effects of herbal and health food products have been infrequently reported such as hepatic damage after use of such products. Four such patients were treated in our department in the course of two years. In all four patients, the use of herbal remedies was the probable cause of serious hepatic damage, but both etiology and pathogenesis were difficult to establish. Two major areas of concern are inaccurate formulation and contaminated preparations. As long as no therapeutic effect can be demonstrated from this type of medicine, serious side effects are unacceptable. A critical attitude should be adopted towards these medicines and the use of them.