Treatments for neonatal jaundice are generally considered both safe and effective. We hypothesized that such treatments would be associated with symptoms of the vulnerable child syndrome, persisting up to 6 months. Mothers of otherwise healthy infants who had jaundice and demographically similar infants without jaundice born at Yale-New Haven (Conn) Hospital were surveyed and compared 6 months after discharge from the hospital. By 6 months, the infants with jaundice had significantly more feeding difficulties, eg, they were less likely to be breast-feeding. Unexpectedly, the mothers of infants with jaundice switched from being less likely to leave their infants with someone else at 1 month to leaving the infants significantly more than mothers of infants in the comparison group. Although the mothers of infants in the comparison group reported a similar number of infant health problems, the mothers of infants with jaundice were more likely to judge the problems as serious and to have taken the infant to an emergency department. The benefits of treating jaundice in otherwise healthy infants should be weighted against the risks of developing the vulnerable child syndrome.