Enterocolitis induced in infants by cow's milk and/or soy protein has been recognized for decades. Symptoms typically begin in the first month of life in association with failure to thrive and may progress to acidemia and shock. Symptoms resolve after the causal protein is removed from the diet but recur with a characteristic symptom pattern on re-exposure. Approximately 2 hours after reintroduction of the protein, vomiting ensues, followed by an elevation of the peripheral blood polymorphonuclear leukocyte count, diarrhea, and possibly lethargy and hypotension. The disorder is generally not associated with detectable food-specific IgE antibody. There are increasing reports of additional causal foods, prolonged clinical courses, and onset outside of early infancy, leading to description of a food protein-induced enterocolitis syndrome. The disorder poses numerous diagnostic and therapeutic challenges. The purpose of this report is to delineate the characteristic clinical features and review the possible pathophysiologic basis to frame a rational strategy toward management.