Cow's milk protein-induced proctocolitis presents with overt rectal bleeding in otherwise healthy infants and is characterized by an eosinophilic infiltrate of the left colonic mucosa. Although it is the most common cause of proctocolitis in infancy, dietary protein-induced proctocolitis had hardly ever been reported in childhood so far. We hereby report 16 otherwise healthy children aged 2-14 yr, who presented over a 6-yr period with persistent or recurrent rectal bleeding related to a mild form of left-sided colitis characterized by a prominent eosinophilic infiltration, focal lymphoid follicle hyperplasia, and a prompt clinical and histological response to a cow's milk-free diet. No patient had a history of food-induced proctocolitis during infancy, and most patients did not show an IgE-mediated response to cow's milk protein. Half of the patients did have other gastrointestinal symptoms, but no systemic symptoms were present and other causes of colitis were excluded by appropriate investigation. Tolerance to cow's milk protein developed in half of the patients within a year. Dietary protein-induced proctocolitis is a relatively common cause of overt rectal bleeding in childhood, and its features are remarkably similar to those of dietary protein-induced proctocolitis of infancy.