Neonatal jaundice with a total bilirubin of 18mg/dl is diagnosed as pathologic jaundice, which is more serious. When the total bilirubin of the newborn is more than 12mg/dl, it is diagnosed as pathologic jaundice, and the causes of pathologic jaundice include excessive production of bilirubin, bilirubin metabolism disorders, and bilirubin excretion disorders. 1. Excessive bilirubin production: bilirubin increases due to destruction of excessive red blood cells and increase of intestinal-hepatic circulation. Hemolysis due to blood group incompatibility is common. 2. Bilirubin metabolism disorders: decreased hepatic uptake and metabolism of bilirubin, resulting in elevated unconjugated bilirubin. Common causes include hypoxia and infection. 3. Bilirubin excretion disorder: bile duct obstruction or hepatocyte excretion disorder leads to hyperbilirubinemia. A common cause is congenital biliary atresia. Hyperbilirubinemia may cause irreversible damage and dysfunction to the nervous system. Therefore, when pathologic jaundice occurs in newborns, they should be hospitalized and treated as prescribed.