A radiofibrinogen catabolism study was performed in 42 patients with liver disease to study the changes that occur in obstructive jaundice and to compare the situation with that in portal cirrhosis. Highest fibrinogen catabolism rates were found in cholangitis and liver contusion. Increased fibrinogen catabolism occurred in portal cirrhosis and in obstruction, and there was increased fibrinolysis in the former and reduced fibrinolysis in the latter. Reasons for increased fibrinogen catabolism include liver cell necrosis and, more commonly, endotoxemia or even overt infection. Results of endotoxin assays suggest that endotoxemia plays an important role in the intravascular coagulation of liver disease.