Adult female beef cattle found positive for stanozolol in the urine were investigated for liver pathology. In all the animals toxic hepatitis was found, including cholestasis, periportal fibrosis and inflammation, focal necrosis and blood filled lacunae. As no clinical data of the cows were available, apart from the history of illegal stanozolol abuse, it is not possible to attribute all changes to the illegal hormone treatment. Moreover, the cows have probably been treated with a cocktail, and apart from stanozolol more anabolic steroids may have been used. Management factors, viral and bacterial infections, former caesarean sections and especially feeding regime may also be responsible for the lesions described. Striking similarities with data from hepatotoxicity found in human body builders using similar agents, however, suggest a major role of stanozolol as causative agent.