The scope blows air into your colon and inflates it, which helps give the doctor a better view. The doctor can remove most abnormal growths in your colon, like a polyp, which is a growth in the lining of the bowel. Polyps are removed using tiny tools passed through the scope. Most polyps are not cancerous, but they could turn into cancer. Just looking at a polyp is not enough to tell if it is cancerous. The polyps are sent to a lab for testing. By identifying and removing polyps, a colonoscopy likely prevents most cancers from forming.
The doctor can also remove tissue samples to test in the lab for diseases of the colon (biopsy). In addition, if any bleeding occurs in the colon, the doctor can pass a laser, heater probe, electrical probe, or special medicines through the scope to stop the bleeding. The tissue removal and treatments to stop bleeding usually do not cause pain. In many cases, a colonoscopy allows for accurate diagnosis and treatment of colon abnormalities without the need for a major operation.
When the doctor has finished, the colonoscope is slowly withdrawn while the lining of your bowel is carefully examined. Bleeding and puncture of the colon are possible but uncommon complications of a colonoscopy.
A colonoscopy usually takes 30 to 60 minutes. You may feel some cramping or the sensation of having gas after the procedure is completed, but it usually stops within an hour. You will need to remain at the colonoscopy facility for 1 to 2 hours so the sedative can wear off.
Rarely, some people experience severe abdominal pain, fever, bloody bowel movements, dizziness, or weakness afterward. If you have any of these side effects, contact your physician immediately. Read your discharge instructions carefully. Medications such as blood-thinners may need to be stopped for a short time after having your colonoscopy, especially if a biopsy was performed or polyps were removed. Full recovery by the next day is normal and expected and you may return to your regular activities.