Two patients who developed biochemical and histological evidence of hepatitis while taking the anti-anginal drug perhexiline maleate are described. The pathological changes were those of mild to moderate fatty change together with a hepatitis which resembled alcoholic hepatitis, including in one patient the presence of material which by light microscopy was indistinguishable from Mallory's alcoholic hyalin. However, the predominantly periportal location of this material contrasted with the centrilobular distribution of Mallory's hyaline. One patient showed, in addition, severe atypia of the hepatocytes which was still present in less pronounced form 10 weeks after stopping perhexiline. The other patient had advanced hepatic fibrosis.