Eosinophilic colitis is one of the clinical manifestations of allergy to cow s milk during the first year of life. We report a series of 9 infants who, under 9 months of age and while clinically well, presented rectal bleeding of variable magnitude, with or without diarrhea, shortly after a cow s milk-based formula was initiated (n=6); yet, 3 cases received only breast feeding. Bleeding disappeared in all patients after milk withdrawal from the diet. Challenges were planned after 12 months of treatment; three patients have not yet reached this moment, 3 had a negative challenge at 12, 18 and 28 months of age and are on a complete diet, and 3 are still on cow s milk free diet because ingestion of milk at 12, 18 and 25 months still induced rectal bleeding. This series of patients gathered in 3 years, follows the trend reported in many countries that there is a relative increase of patients diagnosed with allergy conditions early in life