In the adult, the irritable bowel syndrome is characterized by intestinal transit disorders associated or not with chronic abdominal pain. Two different forms can be seen: in one, pain and constipation are predominant, while in the other, pain and diarrhea alternate. The second form is encountered with predilection in the child. Various terms can be used to name the syndrome including colitis, non specific or benign colitis, irritable bowel syndrome in the child, infantile diarrhea, and others, all of which attests to our ignorance of the pathophysiology of this disorder. This syndrome is by far the most frequent cause of chronic or recurrent diarrhea in the child. Before the age of 3 or 4 years, the principal syndrome is diarrhea, which usually appears before the age of 6 months. Onset is generally brutal, as in acute enteritis or an extradigestive infection (ENT...) but persists, or else, more often, the syndrome appears insidiously over several days. The child has soft or liquid stools of fetid odor in most cases, very rarely sourish, inhomogeneous and in which intact aliments can be found. Stools are often associated with mucous discharge, rarely with blood, and do not contain any pus. Stools are not fatty but occasionally they are sticky and adhere to the pot. During the day, stools change from well formed in the morning to soft in the evening. Their frequency varies from one day to another as well as during a given 24 hour period, ranging from one or two to 10 per day.(ABSTRACT TRUNCATED AT 250 WORDS)