Irritable bowel syndrome (IBS) is recognized to be a common cause of chronic diarrhea without failure to thrive in childhood. Several studies stressed the role of food intolerance as a major factor in the pathogenesis of IBS. The aim of this multicenter study was to investigate the offending role of food in IBS and to compare the therapeutic role of oral sodium cromoglycate versus elimination diet. 153 patients (mean age 4 years) with diarrhea (> 3 stools per day for four days in a week) and abdominal pain for about 10 months were enrolled in this trial. About half of the patients had a family history positive for atopy and 70% of the cases complained of intestinal symptoms after food ingestion. In 17% of the patients Skin Prick test (SPT) resulted positive to at least one food allergen and 87% of positive reactions to SPT was provoked by common foodstuffs. 87% of patients treated with elimination diet (rice, lamb, turkey, lettuce, carrots, sweet potatoes, pears, oil, tea, salt, mineral water, brown sugar) and 97% of patients treated with SCG (mean 63 mg/kg/day) for one month showed a significant improvement of intestinal symptoms. An elimination diet for several weeks can produce, beside a bad compliance (23% of patients admitted to our study didn't strictly follow diet regimen) also a nutritional deprivation. The results of this trial suggest that it's correct to investigate the role of food in children with diarrhea not due to organic diseases and diagnosed such as IBS and to use oral SCG to obtain the improvement of these symptoms.