ABSTRACT—We examined clinical and laboratory data and the liver pathology of 48 patients in whom porphyria cutanea tarda was related to alcohol ingestion, estrogen use and pregnancy, or was idiopathic. Biochemical test results, when abnormal, tended to be mild in most cases, with less than two‐fold elevations of serum aminotransferases and alkaline phosphatase and mild hyperbilirubinemia. Fatty change, liver cell and Kupffer cell hemosiderosis and glycogenation of hepatocyte nuclei were frequent histologic findings in the 58 liver specimens studied. Alcoholic hepatitis, chronic hepatitis and cirrhosis were uncommon. Granuloma‐like lobular aggregates consisting of iron‐ and ceroid‐laden Kupffer cells, chronic inflammatory cells and fat droplets (“lobular lesions of porphyria cutanea tarda”) were found in nearly two‐thirds of specimens and appeared to be the most characteristic form of parenchymal damage in this form of porphyria. These lesions may be associated with pericentral fibrosis in alcoholic as well as estrogen‐treated patients and may remit following thera