The test is performed under sedation and most patients have no recall of the procedure at all. It is important that you do not drive for at least 12 hours afterwards and you must have someone to take you home after the procedure.
Colonoscopy is currently the “best” screening tool for colonic pathology although there is a limit to its sensitivity and rarely small lesions (usually of no consequence) may be missed.
The major although very rare possible complication is bowel perforation which often will require operative (surgical) treatment and bleeding, which usually settles of its own accord, but may require staying in hospital. Sometimes retained gas after the procedure causes abdominal distension and pain.
To ensure that the examination is a success, it is crucial that the bowel is completely empty and some preparation as outlined on the Resources page is required.