Colonoscopy is well-tolerated and rarely causes much pain. You might feel pressure, bloating or cramping during the procedure. Before colonoscopy you will be given a mild sedative and sometimes a painkiller as well. The instrument is passed via the anus and examination of the entire colon is usually possible. The examination is usually straightforward and takes less than 30 minutes to complete. Any abnormal areas are identified and tissue samples may be taken via the instrument. Any polyps can often be removed at the time of the examination.