The normal value of total cholesterol is 2.9-6.0 mmoI/L. Cholesterol is an important indicator of clinical biochemical examination. Under normal conditions, the body synthesizes cholesterol in the liver and ingests it from food. The body synthesizes most of its own cholesterol, with cholesterol from food being a secondary supplement. Cholesterol is found in the blood in lipoproteins, which exist in the form of HDL cholesterol, LDL cholesterol, etc. High-density cholesterol is protective of blood vessels and is often referred to as good cholesterol. Low-density cholesterol, which has an increased risk factor for coronary heart disease if it is high, is often referred to as bad cholesterol. Cholesterol, has the function of synthesizing bile acids, forming cell membranes, and synthesizing hormones. When liver cells are diseased, cholesterol esters are reduced, and the more damaged the liver cells are, the more severely cholesterol esters are reduced. In patients with acute hepatic necrosis, serum cholesterol ester levels may be reduced to very low levels or even disappear as a sign of poor prognosis. Patients with obstructive jaundice have elevated total serum cholesterol lipids, mainly free cholesteryl esters.