Pediatric gastroenterologists have tended to view gastroesophageal reflux (GER) as a disease in and of itself--a disease that can be diagnosed "objectively" with use of numerical data from esophageal pH monitoring and cured with pharmacologic or surgical treatment. What is often forgotten is that the data derived from esophageal pH monitoring and other techniques may identify the presence of abnormal GER but tell nothing about its pathogenesis. The usual approach to infants who feed poorly, vomit, or fail to gain weight is to identify the presence of abnormal GER, rule out underlying organic causes of vomiting, and then diagnosis primary GER disease. The baby is then treated with pharmacologic, dietary, or positional therapy and, ultimately, if these therapies fail to eradicate the symptoms attributed to GER, surgical fundoplication, which stops vomiting regardless of its causes. The pediatric literature on infant vomiting and GER is almost devoid of research into the nature and possible relationships among infant stress, vomiting, feeding difficulties, and failure to grow. Clinically, the quality of the maternal-infant relationship is frequently approached superficially, with psychosocial aspects treated as less important in infants considered to have primary organic disease amenable to medical or surgical treatment. Psychosocial factors in the pathogenesis of the infant's symptoms are often not pursued beyond assessment for possible abuse or neglect. It has been known for centuries that stress or excitement affects gastrointestinal function and symptoms. Although the field of infant psychiatry has produced a substantial literature on the nature of stresses that affect both infants and mothers, the pediatric literature on vomiting and failure to thrive seldom acknowledges the existence or importance of these contributions. In clinical practice, failure to explore psychosocial aspects that may contribute to vomiting, feeding difficulties, or failure to thrive may result in missed opportunities for less invasive, more effective therapy at best, and countertherapeutic treatment at worst. This article describes three functional vomiting disorders of infancy, their distinguishing characteristics, hypotheses regarding their pathogenesis, and principles of comprehensive management.