Activities of key carbohydrate-metabolizing enzymes were determined on biopsied liver tissues obtained from patients with acute and chronic viral hepatitis and postnecrotic cirrhosis of the liver. The results indicated that the activities of fetal or prototype enzymes, low-Km hexokinases, glucose-6-phosphate dehydrogenase and pyruvate kinase type M2 increased, while those of adult type liver enzymes, glucokinase, glucose-6-phosphatase, fructose-1, 6-diphosphatase and pyruvate kinase type L decreased in livers of these cases. Phosphofructokinase activity tended to increase only acute hepatitis. Principal component analysis revealed that the enzyme patterns of acute hepatitis and liver cirrhosis were most deviated from the control and closely resembled those of hepatocellular carcinomas.