With the liberalization of the national maternity policy, the country has faced a peak in childbirth, and obstetric beds in major hospitals have started to be unusually tight. In most tertiary hospitals, mothers who deliver via vaginal delivery are usually discharged 1 day after delivery, and for cesarean deliveries without complications, mom and baby can also be discharged 3 days after delivery. At this time, the newborn’s jaundice may have just appeared and the peak has not yet arrived. Since there is no medical professional to guide the baby after discharge from the hospital, parents need to understand the general medical knowledge of neonatal jaundice and learn to observe and generally determine the baby’s jaundice. Due to the characteristics of bilirubin metabolism in newborns, elevated serum bilirubin levels and yellowing of the skin and sclera are known as neonatal jaundice. Most neonatal jaundice is physiological, appearing 2 to 3 days after birth, peaking in 4 to 6 days and subsiding in 7 to 10 days, with normal feeding, urination and defecation, crying and other general conditions, and no other discomfort, which will not adversely affect the baby. However, if the jaundice appears within 24 hours after birth and does not subside for 2 to 3 weeks, or even continues to deepen and worsen, or reappears after it subsides, it is pathological jaundice, which can cause bilirubin encephalopathy in severe cases, leaving sequelae such as impaired physical activity or hearing impairment, and can be life-threatening in critically ill children. Therefore, pathological jaundice requires prompt consultation and active treatment. So, how can we observe and determine whether a baby’s jaundice is physiologic or pathologic? How to determine the cause of jaundice in general and how to deal with it properly? First, in order to determine whether jaundice is physiological or pathological, parents should observe the following questions: When does jaundice appear in babies? When is the jaundice heaviest? When does it start to decrease? What is the extent of skin jaundice? Is the color of the urine and stool normal? This requires parents to regularly observe the color of their baby’s skin and sclera of the eyes during the first few days of life. If the baby has a darker or redder complexion, you can gently press the tip of the baby’s nose to help observe the jaundice of the skin, and you should observe dynamically and compare before and after to make an accurate judgment. If your baby’s jaundice appears very early, or progresses too quickly, or fades very slowly, it suggests that it may be pathological. In general, jaundice starts on the head and face, and the more it spreads downward, the more severe the jaundice is. If the jaundice exceeds the torso to the position below the abdomen, it indicates that the jaundice is severe and may be pathological, and the baby should be taken to the hospital promptly. If your baby’s jaundice worsens again 2 to 3 weeks after birth, with gray skin, yellow-green sclera, yellow urine, orange water, light-colored stools, or repeatedly white, it indicates pathological jaundice and possible biliary obstruction (obstructive jaundice), so you should consult a doctor promptly. Second, you should learn to analyze the cause of your baby’s jaundice in combination with your baby’s milk intake, stool and temperature: (a) If your baby’s jaundice is generally consistent with the pattern of physiological jaundice, but is heavy and slow to subside, the most common cause is due to inadequate feeding in the early postnatal period, which is a type of breast milk jaundice. Many mothers insist on not adding formula to their babies even if their own breast milk production is still insufficient in the early days after delivery, which leads to insufficient feeding of the baby, causing excessive weight loss after birth and even dehydration, which can lead to increased bilirubin concentration and/or increased absorption in the intestinal and hepatic cycles, making jaundice worse and slow to subside. For more information, please refer to the article “How can I tell if my newborn baby has had enough to eat?” on this website. For more information, please refer to the article “How to tell if your baby is full? (B) Pay attention to the baby’s stool discharge: the excessive bilirubin produced by the baby’s body in the early postnatal period is metabolized by the body and excreted mainly through the stool. If the newborn is delayed or poorly excreted in the early postnatal period, the number of stools per day is low, and in a few cases, meconium intestinal obstruction can occur, which can aggravate the baby’s jaundice, and even pathological jaundice can occur as a result. (iii) Pay attention to the detection of maternal blood type and newborn blood type, and timely detection of neonatal hemolytic disease due to mother-child blood type incompatibility. The mother and child blood types that are most likely to develop hemolytic jaundice are: O for the mother and AB, A or B for the baby; or Rh-negative for the mother and Rh-positive for the baby, and the newborn is not the first born. Therefore, if it has been clear before delivery that the pregnant woman has type O or Rh-negative blood (not the first child), she should be alert to the occurrence of postpartum neonatal hemolytic disease, and it is recommended to follow the doctor’s advice for relevant monitoring. (iv) Combine the baby’s temperature, milk consumption and general condition to determine the presence of other causes such as infection: If the baby has poor spirit, fever, feeding difficulties, etc., beware that the baby has an infection; any infection may aggravate the baby’s jaundice. In addition, if your baby also has poor feeding, slow weight gain, enlarged liver and spleen, yellow urine, and gray stools, which is obstructive jaundice as described earlier, all of which are pathological, you should seek prompt medical attention.