The possible application of Normotest (Hepaplastintest) which was developed for determining the activity of the clotting factors was tried, as a liver function test detecting dysfunction of proteo-metabolism in liver cell.Transition of Hepaplastintest value was followed in the clinical process of patients of various liver diseases (65 cases; 17, acute hepatitis 7, persistent hepatitis 13, chronic inactive hepatitis 3, chronic active hepatitis 5, chronic alcoholic hepatitis 13, liver cirrhosis 5 cholestasis) and 2 liver failure in comparison with the value of 27 healthy subjects (12 male and 15 female). In this determination, correction by Hematocrit value was made.Average value of the healthy controls was 78.5% (male 82.6%, female 75.2%), ranging from 64% to 105%.In cases of acute hepatitis, the average value was depressed down to 48.5% at the early stage, and turned for the normal range showing 69.9% (average) with recovery. But in severe cases, the low value was maintained, and especially in cases of fulminant hepatitis, conspicuous low value was indicated. In cases of chronic inactive hepatitis, 72.3% (average) was observed, which did not show such mentionable low values; but in chronic active hepatitis, low value of 45.6% (average) was indicated. In cases of persistent hepatitis and chronic alcoholic hepatitis, 68.1 and 65.2% (average) were shown, respectively. In liver cirrhosis, quite low value of 40.8% (average) was indicated and many cases of them did not recover to the normal range. In cases of cholestasis, however, the value was in the normal range, and its average figure was 78.7%.Furthermore, as to the percentage of the cases showing low value (below 65%) of Hepaplastintest in patients of liver diseases, the largest number (20/38) was observed in the group of HBs-antigen positive cases, next (21/43) in the group of HBs-antibody positive cases, and in the group of HBs-antigen and antibody negative cases, small number (11/29) was observed obviously.Considering the above-mentioned findings, this test for determining the activity of the clotting factors was suggested to be a useful indicator for judging the severity of liver damage, the clinical course and the prognosis of acute and chronic hepatitis, and liver cirrhosis; and for the differential diagnosis between those liver cell injury and cholestasis.