The changes in coagulation and fibrinolysis were studied in cases of hepatocellular carcinoma with (n = 20) and without (n = 8) transcatheter hepatic arterial embolization (TAE). The plasma levels of thrombin-antithrombin III complex (TAT) and alpha 2 plasmin inhibitor complex (PIC) were significantly elevated after TAE, concurrently with a decrease in antithrombin III and antiplasmin (alpha 2-plasmin inhibitor) levels. The elevation of TAT was most significant (2.4-fold of the pre-TAE level) on day 3, whereas that of PIC was relatively less (1.3-fold on day 3). Tissue plasminogen activator in blood was also significantly increased on day 1, but it was decreased thereafter, although plasminogen activator inhibitor (PAI) remained high for at least 7 days after TAE. In contrast, such hematological changes were not observed in patients without TAE. Thus, both coagulation and fibrinolysis were activated after TAE, but its effect on fibrinolysis was less prominent, due probably to the increased synthesis of PAI.