The presence of IgG over the hepatocyte's surfaces in ethanol- and/or carbon tetrachloride-pretreated rats was demonstrated as a very thin lineal fluorescent deposition around the membrane. The percentage of parenchymal IgG-positive liver cells ranged between 15 and 100% in all animals of treated groups. This suggests that ethanol may induce hepatic injury mediated by IgG autoantibodies which may be a response to an antigenical determinant present in hepatocytes altered by ethanol and/or carbon tetrachloride treatment.