 Carbon dioxide insufflation during colonoscopy significantly reduces discomfort pain, bloating and flatulence during up to 24 hours after the procedure. So far, it has not been studied in inflammatory bowel disease patients who represent specific patient population indicated for colonoscopy. They are characterized by younger age, structural changes of the colon including intestinal resections and need for repeated and frequently difficult procedures.The study was designed to evaluate discomfort during 24 hours after the carbon dioxide insufflation colonoscopy in comparison to standard air insufflation colonoscopy. 