In the 1950s, exchange transfusion to keep the total serum bilirubin below 20 mg/dl was shown to be an effective way of preventing kernicterus in babies with erythroblastosis fetalis. For the last 15 to 20 years this level has also been used to determine the need for intervention in healthy full-term infants who do not have hemolytic disease. A critical review of all the available data including six studies from the collaborative perinatal project (more than 30,000 infants) and several smaller studies of term infants without hemolysis reveals essentially no evidence of adverse effects of bilirubin on IQ, neurologic examination, or hearing. The investigation and treatment of normal infants with jaundice is expensive and potentially harmful. We need to reassess our approach to hyperbilirubinemia in healthy full-term infants.