Colonoscopy is currently most effective procedure used for detecting colon cancer especially in the early stages. Screening colonoscopies are performed in the symptom-free patients at risk of familial colon cancer. During colonoscopy air commonly used to insufflate the bowel may be retained after the procedure causing pain and discomfort to the patients. One of the methods used to reduce pain and discomfort is insufflation of carbon dioxide (CO2) instead of air during colonoscopy.