Hirschsprung's disease is one of the more common causes of childhood bowel obstruction. The disease can cause enterocolitis which, untreated, may result in considerable mortality. We describe our evaluation of two infants who suffered from intractable diarrhea of infancy secondary to Hirschsprung's disease. We found that mucosal damage to the small bowel and disaccharidase deficiency are among the most important mechanisms producing this complication. Therefore, management of enterocolitis including parenteral alimentation should proceed as soon as the complication is observed.