A colonoscopy usually takes about 15-30 minutes to do. The exact time varies from person to person. If there are no obvious lesions in the bowel, the examination will take less time. If polyps, ulcers and other lesions are found during the colonoscopy and polypectomy or endoscopic pathology is required, the time required will be extended accordingly. In addition, the time to do painless colonoscopy and ordinary colonoscopy is also different. Normally, it takes about 15 minutes to do ordinary colonoscopy. Painless colonoscopy requires anesthesia first, and there is an anesthesia recovery period after the colonoscopy, which takes about 30 minutes in total. It is important to do a good bowel cleansing before the colonoscopy so as not to affect the test results. It is recommended that you talk to your doctor in advance about how long it will take to do a colonoscopy.