Bilirubin includes indirect bilirubin as well as direct bilirubin. Indirect bilirubin is produced by the breakage and lysis of aging red blood cells, which is transformed into direct bilirubin after uptake by the liver and metabolized out of the body by the liver into a series of processes in the enterohepatic circulation, which is the overall bilirubin metabolism process. The elevation of direct bilirubin as well as indirect bilirubin also has different clinical significance in biochemical indicators. An elevation of indirect bilirubin may be too indicative of hemolytic changes; an elevation of direct bilirubin may be indicative of biliary obstruction and obstructive disease; an elevation of both direct and indirect may be indicative of hepatogenic and hepatocellular damage. Although different indicators represent different meanings, it depends on the relative clinical and other laboratory tests. If the metabolic process of bilirubin is abnormal or the metabolism is abnormal, systematic diagnosis and treatment should be carried out at the local gastroenterology department.