Bloating, gas, pain and diarrhea are common complaints. Routine investigations are negative; these patients are labeled as IBS. In these patients, whether testing for carbohydrate malabsorption or small intestinal bacterial overgrowth (SIBO) is useful is unclear. We aim to assess the prevalence of SIBO, fructose and lactose intolerance, the usefulness of breath tests, and predictive value of pre-test symptoms.