Colonoscopy enables the endoscopist to look at the inside of the large bowel.

Endoscopists may use the procedure to find the cause of change in bowel habit, rectal bleeding or abdominal pain to check for signs of cancer. With colonoscopy, the endoscopist can see bleeding, inflammation, abnormal growths and ulcers in the colon and rectum.

For the procedure, the patient lies on their left side initially. If the patient has decided upon having sedation, this is given before the start of the procedure. Entonox (gas and air) is also available to help with any discomfort. The endoscopist inserts a flexible, lighted tube into the rectum and guides it into the colon. The scope transmits an image of the inside of the bowel to a screen, so the endoscopist can examine the lining.

If anything unusual is in the rectum or colon, like a polyp or inflamed tissue, the endoscopist can remove a piece of it using instruments. The endoscopist will send that piece of tissue (biopsy) to the laboratory for testing.

Complications are uncommon; however, bleeding or perforation are possible.

Colonoscopy takes about 20 – 30 minutes. During the procedure patients may feel pressure and slight cramping in the lower abdomen. If patients are sedated they will need to rest at the Endoscopy Unit for one to two hours until the medication wears off.