Hepatic blood flow (HBF) has been reported to reflect liver cell mass. HBF was studied in 21 patients with chronic active hepatitis (CAH) and in 20 patients with liver cirrhosis (LC). It was correlated with such indices of liver protein synthesis as serum albumin, Normotest, plasma activity of antithrombin III, prekallikrein, alpha 2-antiplasmin and plasminogen. No correlation between HBF and the examined parameters was seen in CAH. HBF correlated with all the indices of liver protein synthesis in LC, thus suggesting that serum albumin, antithrombin III, Normotest, prekallikrein, plasminogen, and alpha 2-antiplasmin could reflect the residual liver cell mass in LC.