Close to one out of every 1,000 people having this test done may have a tear caused by the procedure in their intestine wall, which might require surgery for repair.
Some people have a small amount of bleeding after the procedure, if a biopsy has been taken.
Some bleeding complications require another colonoscopy or surgery to repair. It is possible to have an allergic reaction to the medicines that are used for sedation and these medicines can also cause heart or breathing complications in a small number of patients. Sometimes patients feel some discomfort with bloating or pain after the procedure for a few days.