The relationship between levels of coagulation Factors V and VIII and disease severity was evaluated in 33 patients with alcoholic liver disease, and related to outcome in the 23 with severe acute alcoholic hepatitis. Factor V levels in acute alcoholic hepatitis were significantly lower than in inactive alcoholic liver disease (median 28% vs 74%), and both results were lower than values in 10 control subjects (median 101%; P less than 0.001 and P less than 0.002, respectively). Plasma Factor VIII concentrations were not significantly higher in alcoholic hepatitis than in inactive alcoholic liver disease, although both results significantly exceeded control values (median 163% and 151% vs 104%; P less than 0.005 and P less than 0.05, respectively). In the 18 in-patients with alcoholic hepatitis who survived, admission factor V (median 32%) was higher, and admission serum bilirubin (65 mumol/l) and discriminant function score (derived from prothrombin time and bilirubin: median 31) were lower than in the four who died and one who received a liver transplant (median 16%, 527 mumol/l and 113; P less than 0.005, P less than 0.005, P less than 0.05, respectively). An admission Factor V level less than 15% correctly predicted outcome in a greater number (87%) of cases than admission discriminant function greater than 100 (83%), bilirubin greater than 300 mumol/l (83%) or prothrombin ratio greater than 1.5 (78%). This predictive accuracy increased to 100% for minimum Factor V less than 15% and was again superior to maximum discriminant function greater than 100 or greater than 300 mumol/l (both 83%) or maximum prothrombin ratio greater than 1.5 (78%).(ABSTRACT TRUNCATED AT 250 WORDS)