Thirty nine children with recurrent abdominal pain aged between 5.5 and 12 years, underwent endoscopic duodenal biopsy to find out if there were any duodenal inflammatory changes, and if there was a relationship between duodenal inflammation and intestinal permeability to 51Cr-EDTA. Duodenal inflammation was graded by the duodenitis scale of Whitehead et al (grade 0, 1, 2, and 3). In 13 out of 39 patients (33%) definite signs of inflammation were found (grade 2 and 3). Intestinal permeability to 51Cr-EDTA in patients with duodenitis (grade 1, 2, and 3) was significantly higher (4.42 (1.73)%) than in patients with normal (grade 0) duodenal biopsy appearances (3.3 (0.9)%). A significant association was found between duodenal inflammation and abnormal intestinal permeability. Our results give further evidence that there is an intestinal origin of these patients' complaints.