Neonatal jaundice is one of the most common conditions in newborns, and it can be categorized into physiological jaundice and pathological jaundice. Physiological jaundice is due to the bilirubin metabolism characteristics of newborns. Generally, about 50%-60% of full-term infants and 80% of preterm infants may experience physiological jaundice. The typical pattern is that the healthy condition remains good, with jaundice appearing on the second to third day after birth for full-term infants, reaching a peak on the fourth to fifth day, and then gradually subsiding, but generally disappearing no later than two weeks. For preterm infants, jaundice usually appears from the third to fifth day after birth, peaks between the fifth and seventh day, and then gradually declines, typically not exceeding four weeks. Therefore, if it is physiological jaundice, it has a certain timeframe. If it is pathological jaundice, the duration of jaundice can vary depending on the cause, whether there was timely intervention and treatment, and the effectiveness of the treatment. Thus, if the jaundice progresses quickly and is severe, it is crucial to promptly visit the hospital, where neonatal doctors can assess the baby's condition and intervene if necessary.