BACKGROUND: In intestinal food allergy, the non-specificity of gastrointestinal symptoms and the limited access to the reacting organ are the reasons for the limited understanding of the pathophysiology of this disease and the difficulties in establishing an appropriate diagnosis in the individual patient. OBJECTIVE: To develop an in vitro model reproducing pathophysiological mechanisms of IgE mediated food allergy. METHODS: Distal duodenum biopsies of nine patients with food allergy and 10 control subjects were cultured for 3 h with medium alone and with 1 mg/ml of peptic-tryptic digest of wheat gliadin, wheat albumins, and apple proteins. Each biopsy was used for conventional histological examination and for immunohistochemical detection of IgE-positive cells. We have also analyzed the expression of tight junction proteins, occludin, claudin-1, and ZO-1 by immunoconfocal microscopy. Histamine and tryptase release were measured in the culture medium and collected at 0, 30 min, and 3 h of culture using an enzyme and radio immunoassay, respectively. RESULTS: Exposure of small intestinal biopsy specimens of patients with food allergy to food allergens led to a significative increase of IgE-positive cells with a significative increase of histamine and tryptase release and an altered expression of tight junction proteins. No differences were found in intestinal biopsies of controls, cultured with or without food antigens. CONCLUSIONS: Small intestinal organ culture is a functional model of food allergy and could be considered as an in vitro oral food challenge, with evident reduction of costs and risks for the patients.