Infants and toddlers with constipation usually have a history of infre
quent, hard and painful bowel movements, often accompanied by screamin
g and stool-holding maneuvers. Encopresis, the intermittent and involu
ntary passage of formed-to-liquid feces, is common. Although constipat
ion most often has a functional cause, the history and physical examin
ation should rule out anatomic, endocrinologic, metabolic or neurologi
c causes. Hirschsprung's disease-aganglionic megacolon-is a congenital
cause of severe constipation that occurs in one of every 5,000 births
. Treatment consists of fecal disimpaction, laxatives to prevent futur
e impaction, promotion of regular bowel habits and, finally, toilet tr
aining. Parents should be reassured that although this disorder is not
life-threatening, several months to years of supportive intervention
may be required for effective treatment.