Not only many food substances but also other substances such as house dust(HD) may serve as causative allergens of allergic gastroenteropathy. To clarify the causative allergens and the pathogenesis of allergic gastroenteropathy, an oral loading test using HD, was applied to two patients with allergic gastroenteropathy caused by an unknown antigen, and with HD-sensitivity, and 24 bronchial asthmatics with or without HD-sensitivity, ther were examined using the ultrasonography of stomach reported previously. Two patients with gastroenteropathy showed a positive skin test and IgE RAST to HD, although they had bronchial asthma in the past history. Peripheral blood eosinophils in the 1st and 2nd patients showed a high (max 78%) and slightly increased (9%) value. The precipitating antibody in the two cases was negative, but lymphocyte blastogenesis to HD was enhanced in one case. During the oral loading test using HD, both patients had abdominal pain at immediate and late phase and acceleration of gastric peristalic movements was confirmed by ultrasonography. One of the 2 patients showed a strong gastrointestinal reaction during the delayed phase. LTC4 and histamine were considered to be involved in the abdominal pain of these cases. One of the 12 patients with bronchial asthma and HD-sensitivity showed an immediate reaction in oral loading test without abdominal pain, suggensting a correlation of the hypersensitivity between the bronchi and the digestive tract, including 2 former cases.