What is a colonoscopy?

The NHS Bowel Cancer Screening Programme helpline is 0800 707 6060

A colonoscopy is an investigation that involves looking directly at the lining of the large bowel. A sedative is given and then a thin, flexible tube with a tiny camera attached (a colonoscope) is passed into the back passage and guided around the bowel. If polyps are found, most can be removed painlessly, using a wire loop passed down the colonoscope tube. These tissue samples are then checked for any abnormal cells that might be cancerous.

  • About five in 10 people who have a colonoscopy will have a normal result.
  • About four in 10 will be found to have a polyp, which if removed may prevent cancer developing.
  • About one in 10 people will be found to have cancer when they have a colonoscopy.