Skin yellowing is common in newborns, and visual jaundice is observed in approximately 80-90% of babies under normal circumstances. The presence of jaundice in newborns should be identified as physiological jaundice under normal conditions or pathological jaundice under abnormal conditions. This is important for both the diagnosis and management of neonatal jaundice. Physiologic jaundice in newborns is early neonatal jaundice due to the characteristics of bilirubin metabolism, except for various pathologic factors, serum unconjugated bilirubin increased to a certain range of neonatal jaundice. Physiologic jaundice in full-term infants mostly appears 2 to 3 days after birth, peaks in 4 to 5 days, and completely subsides no later than 14 days after birth, with varying degrees of severity of jaundice, the lighter being limited to the face and neck, the heavier extending to the trunk, extremities and sclera, but not exceeding the wrist and ankle, with golden feces and colorless or only light yellow urine, generally without any symptoms. The total serum bilirubin value for physiological jaundice in full-term infants should be less than 153.9 umol/l 24 to 48 hours after birth and less than 220.6 umol/l 48 hours after birth. Premature infants are more likely to have jaundice even if the value is in the “normal” range due to more immature liver function, low serum albumin levels, imperfect blood-brain barrier development, and many combined abnormalities. “Therefore, there is no concept of physiological jaundice, and active intervention should be made when jaundice occurs. The total serum bilirubin value in preterm infants should be less than 205.2 umol/l 24 to 48 hours after birth and less than 256.5 umol/l 48 hours after birth. Pathological jaundice in newborns includes: jaundice within 24 hours after birth, jaundice exceeding the standard at different days of age, jaundice rising faster or progressively increasing every day, abnormal serum direct bilirubin, jaundice lasting for too long etc. Some unprofessional medical professionals or parents believe that jaundice in a full-term baby within 14 days of birth is normal physiological jaundice, and that jaundice that does not subside after 14 days is abnormal; in fact, if the jaundice value in a full-term baby within 14 days of birth exceeds normal, it is also pathological jaundice. There are many causes of pathological jaundice, such as hemolysis, sepsis, viral infections, delayed fetal excretion, etc. Treatment depends on the condition. In some cases, pathological jaundice is too high and can lead to an adverse consequence – bilirubin encephalopathy. If your baby develops jaundice, parents should take your baby to a specialist as soon as possible. The neonatologist will determine whether your baby needs to be hospitalized and the treatment plan for jaundice based on your baby’s gestational age, daytime age, and jaundice values.