ABSTRACT—Cytotoxicity of peripheral blood lymphocytes for autologous hepatocytes has been studied in 18 patients with different histological types of alcoholic liver disease. Cytotoxicity was significantly increased in five of ten patients with cirrhosis and/or alcoholic hepatitis but in only one of eight with fatty infiltration or minor histological changes. The cytotoxic effect of T‐ and non‐T‐effector cells was separately evaluated in 11 cases. Of six patients with alcoholic hepatitis, non‐T lymphocyte cytotoxicity was increased in five and T‐cell in only one. These preliminary results are consistent with the concept that autoimmune reactions may play a role in the development and progression of alcoholic hepatitis and cirrhosis, although it is likely that direct hepatotoxic effects of ethanol or its metabolites are also important in determining the pattern of liver injury and perhaps in initiating the immune reactions observed in