Herbal hepatotoxicity: an expanding but poorly defined problem.

Alternative therapies, including herbal remedies, are popular in the general population and even more so among patients with liver disease. The use of such products is now well established in western society and is no longer confined to traditional medicine practitioners in Asia, Africa and the Middle-East. Their perceived benefits remain generally unproven and concern about adverse effects is leading to closer scrutiny of these products. Herbal hepatotoxicity has been recognized for many years, but new agents are constantly being identified. The varied manifestations of liver injury include steatosis, acute and chronic hepatitis, hepatic fibrosis, zonal or diffuse hepatic necrosis, bile duct injury, veno-occlusive disease, acute liver failure requiring liver transplantation and carcinogenesis. Potential interactions between herbal medicines and conventional drugs may interfere with patient management. Concurrent use of such products is not often disclosed unless specifically sought after and can lead to perpetuation of the liver injury. The present review focuses on emerging herbal hepatotoxins, newer patterns of liver injury among the older agents and provides an updated tabulation of the adverse effects of major herbal hepatotoxins. Key issues of diagnosis and prevention of this growing problem are addressed. Continued public education, physician awareness and more stringent licensing are required to tackle this growing problem.