Both physiological jaundice and pathological jaundice are due to various causes of excessive bilirubin production and insufficient excretion resulting in the accumulation of total bilirubin in the body. The normal value of total bilirubin in neonates is the upper limit of serum bilirubin for physiological jaundice in neonates: <12mg/dl in term infants and <15mg/dl in preterm infants. Generally speaking, physiological jaundice exceeding 12mg/dl can generally Regardless of whether the jaundice is physiological or pathological, the greater the value of total serum bilirubin, the more it accumulates in the body and the more severe the symptoms of jaundice will be. In addition, the greater the increase in total bilirubin, the more severe the symptoms of jaundice. Strictly speaking, there are different normal values for different days of age, and for preterm infants, there are different normal ranges for different days of age and different gestational ages. The need for intervention in newborns depends not only on the level of bilirubin, but also on the composition of the bilirubin, whether the bilirubin is indirect or direct. It also depends on the age of the child. For children less than one week old, special attention should be paid, but for older newborns, it is not so stressful.