The normal duration of blue light for jaundice depends on the severity of the jaundice and generally ranges from 2-48 hours, so it is impossible to generalize. Jaundice is caused by abnormal bilirubin metabolism, resulting in elevated bilirubin levels in the blood. Blue light irradiation can change the structure of bilirubin and effectively reduce unconjugated bilirubin in the serum so that it can be excreted rapidly from bile and urine to treat neonatal jaundice. Pathological jaundice in newborns requires prompt treatment such as blue light irradiation, usually ranging from 2-48 hours of irradiation or, depending on the specific situation, continuous or intermittent irradiation, with total bilirubin less than 13 mg/dl to stop treatment, usually no more than 4 days. If the jaundice level is particularly high, blue light irradiation can be combined with medication and, if necessary, blood exchange therapy. During blue light irradiation, care should be taken to protect the newborn’s eyes with black eye shields to avoid damage to the retina; the newborn needs to be naked during irradiation, with cloths covering the perineum and anus. This method has fewer side effects and is highly effective.