Rats were fed liquid food containing ethanol in concentrations ranging from 1–5 % for 13 weeks. Livers were removed for histopathology and the liver cytosolic protein fraction was prepared and used for two-dimensional gel electrophoresis (2D-PAGE). Polypeptides were visualized by silver staining. Scanning was made for estimation of the relative abundance of protein in each polypeptide spot in the gels and for comparison between rats. Visual inspection and scanning of gels with the stained polypeptide spots obtained after equilibrium isoelectric focusing and non-equilibrium pH gradient electrophoresis revealed that: (1) within the control rat and ethanol-treated rat livers the numbers of polypeptide spots detected using isoelectric focusing in the first dimension were approximately 500 and for non-equilibrium pH gradient electrophoresis 400; (2) in the control group the variation in the estimated amount of protein in each spot was remarkably small; (3) pronounced differences in the relative abundance of protein in several of the spots was observed in the ethanol-exposed rats as compared to controls. Dose-response relations and possible causes for the effects of ethanol are discussed.