Psychological stress (PS) has various influences on allergic diseases. Although gastrointestinal sensitization induces hypersensitivity reactions in the skin, such as urticaria and dermatitis, due to food or drug allergy, the effect of PS on the gastrointestinal sensitization phase remains unclear. We administered 2,4,6‐trinitrochlorobenzene (TNCB) to BALB/c mice intragastrically (gastrointestinal sensitization). After 4 days, we elicited a cutaneous delayed‐type hypersensitivity (DTH) reaction by applying TNCB to the ear. We examined the effects of immobilization stress (IS) before gastrointestinal sensitization and elicitation on the cutaneous DTH (CDTH) by measurement of the thickness of the swollen ear, morphological changes and the number of Ia molecule‐positive Langerhans cells (Ia + LC) in the forestomach, and serum corticosterone (CORT) concentration. In addition, we studied the effect of pre‐administration of a glucocorticoid receptor antagonist (RU486). CDTH was suppressed significantly with application of IS for more than 6 h prior to gastrointestinal sensitization. Simultaneously, Ia + LC became smaller and round in shape and decreased in number. The serum CORT concentration doubled following IS for more than 2 h, and these changes were suppressed by pre‐administration of RU486. The results indicate that IS suppresses gastrointestinal sensitization, probably in association with suppression of the antigen‐presenting function of the Ia + LC by elevation of steroid hormones. Copyright © 2008 John Wiley & Sons, Ltd.