Ten patients with irritable bowel syndrome were evaluated for food hypersensitivity with skin testing (IgE) and IgG serum antibodies (RAST panel) to common food antigens. Patients also underwent an open elimination diet for 2 weeks followed by a 48-hour challenge of each food that was considered to be suspicious from patients diary, positive skin prick test, and/or positive IgG antibodies. Six patients had positive skin scratch test results and only one patient had RAST IgG food antibodies greater than 3,000 cpm which is a marked increase above normal. None of the patients however had an exacerbation of their irritable bowel symptoms with a food challenge. We conclude therefore that positive skin testing and IgG serum antibodies are not reliable indicators of food hypersensitivity in irritable bowel syndrome and that food hypersensitivity does not seem to play a role in the symptoms related to the irritable bowel syndrome.