Recent investigations of several authors on portal venous and systemic endotoxemia in healthy adults have shown that endotoxins absorbed from the intestinal mucosa are found in portal venous blood, cleared by the RES of the liver and usually cannot be determined in peripheral blood. In patients with liver disease, however, there was often a reduced endotoxin clearance with spillover of endotoxin resulting in systemic endotoxemia. Among the complications of systemic endotoxemia, hepatocytotoxicity, pyrogen reaction, disseminated intravascular coagulation, impaired renal function, and endotoxic shock are most hazardous. In addition, O-antibody titers and lipid-A-antibody titers were found to be higher in patients with liver disease and in patients with Crohn's disease than in control groups. The investigations indicate that intestinal endotoxins are of importance in the pathogenesis of liver disease and of Crohn's disease and that reduction of intestinal endotoxins by antibiotics may be of value in the therapy of these diseases.