Physiological jaundice in infants usually does not require special treatment and can generally subside naturally under dynamic observation, i.e. it is self-limiting. Neonatal jaundice is usually characterized by yellowing of the skin, mucous membranes and sclera during the neonatal period due to elevated blood bilirubin levels caused by abnormal bilirubin metabolism. Generally, jaundice appears 2-3 days after birth, reaches its peak in 4-6 days, and begins to subside in 7-10 days. Physiologic jaundice in preterm infants is slower to subside and can be delayed for 3-4 weeks.