Complementary and alternative medicine (CAM) has been used for centuries in China and Japan to treat various illnesses, including viral hepatitis. Several therapeutic approaches constitute CAM, the most relevant for this review being the use of herbals. However, profound disagreements exist between conventional and alternative medicine practitioners regarding their value. Western medical advocates cite deep concerns about the purity of most herbals because of lack of standardized production, the paucity of pharmacokinetic data, the fact that few well-designed randomized, controlled trials of these products have been performed and the evidence that some herbals have been responsible for severe adverse effects. Nevertheless, many in the public, even in western countries, turn to the use of herbals, believing that they must be safe and effective because they are 'natural' and have been used for centuries, and because of dissatisfaction with conventional medicine. Accordingly, their use in western countries and the costs incurred have increased each year. While there is evidence that some herbals have physiological effects, there still is insufficient evidence to recommend their use. This paper reviews the classification, epidemiology and philosophy of CAM, and the reasons advanced for herbal use to treat viral hepatitis. The criteria necessary to develop a potential pharmacological agent are presented, as well as the requirements for conducting a scientifically valid treatment trial of herbals. Five herbals used in the past to treat viral hepatitis are reviewed and evaluated for the quality of their studies and mention is made of herbals known to have adverse effects.