Freeze dried Eupatorium adenophorum leaf powder mixed in rat feed at a level of 25% elicited hepatotoxicity. The affected animals were jaundiced and had marked increase in plasma bilirubin levels and activities of alkaline phosphatase, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase. The liver of intoxicated animals had focal areas of necrosis and bile duct proliferation. Elevation in plasma bilirubin concomitant with alterations in enzyme profile and histopathological lesions are consistent with liver injury and cholestasis. This is the first report of the toxicity of E. adenophorum to rats. Copyright (C) 1999 Elsevier Science Ltd.