Although successful breastfeeding confers compelling advantages to infants and mothers, inadequate breastfeeding can result in critical infant failure-to-thrive and hypernatremic dehydration. Potential catastrophic infant outcomes can occur when enthusiastic promotion of breastfeeding outpaces necessary support services and management. Such cases often involve underlying maternal and infant breastfeeding risk factors, made deadly by parental and professional misconceptions and knowledge deficits or health care system failures. An early follow-up visit a few days after discharge allows at-risk infants to be identified before they lose excessive weight and at a time when intervention can easily correct most breastfeeding problems before they become complicated by insufficient milk. Those who enthusiastically promote breastfeeding for its many health benefits must confront the reality of breastfeeding failure and implement necessary changes in medical education and support services to foster successful outcomes in breastfed infants.