The authors investigated electron microscopically the biopsy material of 48 chronic alcoholic liver patients. On the basis of clinical and histological criteria 5 stages were differentiated: fatty liver, fatty liver with increased mesenchymal activity, acute alcoholic hepatitis, chronic alcoholic hepatitis, alcoholic cirrhosis. In each group changes of liver cell organelles and mesenchymal cells were compared. In this investigation it was demonstrated that liver cell damage--except for acute alcoholic hepatitis was not parallel with the severity of the clinical picture. On the contrary, the proliveration of mesenchymal cells, signs of its secretory activity and fibre forming, were in correlation with the progression of liver disease. The authors suggest that an intermediate stage must be taken into account between acute alcoholic hepatitis and alcoholic cirrhosis: the chronic progressive alcoholic hepatitis. It reminds morphologically to a great extent of the active chronic hepatitis and it is characterized not by severity of the injury of liver cell organelles, but by great proliferation of mesenchymal cells and lymphoid infiltration.