One more study which says flatulence is due to higher fermentation in the colon. it is surprising that basal fecal fermentation is higher in normal subjects while the difference between basal fecal fermentation and fecal fermnentation with lactulose was higher in the patients with flatulence. Also the fecal fermentation with lactulose was higher in patients than normals. This was a pretty large study with 126 patients and 30 normals. i wnder what lower basal fecal fermentation means. http://www.ncbi.nlm.nih.gov/entrez/query.f...t_uids=15241490 The first study was directly related with IBS patients Abnormal colonic fermentation in irritable bowel syndrome."Colonic-gas production, particularly of hydrogen, is greater in patients with IBS than in controls, and both symptoms and gas production are reduced by an exclusion diet. This reduction may be associated with alterations in the activity of hydrogen-consuming bacteria. Fermentation may be an important factor in the pathogenesis of IBS." http://www.ncbi.nlm.nih.gov/entrez/query.f...st_uids=9777836