Double-balloon enteroscopy (DBE) was introduced 2001 for visualizing the entire small bowel. In 2008, a novel balloon-assisted enteroscope system has been developed using only a single balloon (single-balloon enteroscope, SBE). SBE was designed to facilitate diagnosis and treatment of the small bowel. The investigators could demonstrate the both endoscopic procedures are equally suitable in the clinical routine. In both balloon-assisted endoscopic procedures (balloon-assisted enteroscopy (BAE)) it is mandatory to insufflate gas into the bowel to secure good visualization. All endoscopes used for GI endoscopy provide a gas insufflation unit. Currently, many endoscopy units use air for this purpose. The use of air, however, is far from ideal for insufflation in GI endoscopy. During and after GI endoscopy, significant amounts of air are usually retained in the bowel segment inspected. This air has to pass the GI tract and exit physiologically through the rectum. Thus, abdominal pain and discomfort during and after the examination due to the retention of air have been shown to be very common during and after endoscopic procedures. Carbon dioxide gas (CO2), unlike air, is rapidly absorbed from the bowel. Within minutes, several liters of CO2 can be absorbed from the GI tract. The use of CO2 has been shown to result in more comfortable examinations in both colonoscopy and flexible sigmoidoscopy in several randomized trials. In these studies, CO2 insufflation had almost completely reduced procedure-related pain and discomfort.