Ascitic fluid reinfusion in severe cirrhosis has frequently been associated with intravascular coagulation (DIC). A low-grade DIC has been postulated to be present in liver cirrhosis. PT, APTT, fibrinogen, plasminogen, antiplasmin, fibrin degradation producers (FDP), euglobulin lysis time, tissue plasminogen activator, and fibrinopeptide A were investigated both in the plasma and ascitic fluid of cirrhotic patients before and after the concentration-reinfusion technique. Our results indicate that increased thrombin formation associated with hyperfibrinolysis is present in the plasma of cirrhotic patients. In ascitic fluid very high levels of thrombin and fibrinolysis activation were found. We conclude that (1) a DIC-like picture exists in ascites and (2) after ascites reinfusion procedures, ascitic fluid is the principal factor in the pathogenesis of DIC. During ascitic fluid reinfusion heparin treatment could be used successfully.