The yellow eyes of a three-day-old baby may be physiological jaundice or pathological jaundice. Most of the former do not need treatment, while the latter need timely medical attention. 1. Physiological jaundice: the ability of newborns to take in, combine and excrete bilirubin is obviously not as good as that of adults, and the production of bilirubin is more than the excretion of bilirubin, so it is very easy for physiological jaundice to occur in newborns. For full-term infants, physiologic jaundice appears 2-3 days after birth, reaches its peak in 4-5 days, subsides in 5-7 days, and does not exceed 2 weeks at the latest. Most of the physiologic jaundice in newborns do not need treatment, and dynamic observation is enough. 2. Pathological jaundice: pathological jaundice may appear within 24 hours after birth. There are many causes of pathologic jaundice in newborns, and the possible causes include excessive bilirubin production, hepatic bilirubin metabolism disorder, bilirubin excretion disorder, and increased enterohepatic circulation. Babies with yellow eyes three days after birth should seek medical attention to identify the cause and treat it promptly to avoid delaying the condition.