The liver is the main organ of cholesterol, triglyceride metabolism and lipoprotein synthesis. In diffuse parenchymatous diseases which lead to cirrhosis of the liver a decline of VLDL and HDL particles occurs, as well as a decline of apo-B, apo-E lipoprotein (a). In cholestatic diseases the levels of free cholesterol, phospholipids and sometimes also triglyceride levels rise, in the termonal stage they decline again. A specific marker of cholestasis is the presence of abnormal lipoprotein X, which is formed from non-esterified cholesterol and phsopholipids regurgitating from bile. Primary lipid disorders may then cause liver disease--steatosis. The main risk factors are hypertriglyceridaemias. In the pathogenesis of liver steatosis in particular an increased supply of fatty acids into the liver, is involved, as well as defects in the process of VLDL synthesis and triglyceride release from the liver into the circulation. Hypercholesterolaemia is not a risk factor of steatosis.