Common Procedures

Common Procedures > Colonoscopy

What is a colonoscopy?  

A colonoscopy is a test that looks at the inner lining of an individual’s colon (large intestine).

Often, people have a colonoscopy as a screening test to check for polyps or for cancer in the colon or rectum. Polyps are growths in the colon that might turn into cancer. If you have polyps, the doctor can usually take them out during the colonoscopy (unless they are larger or are suspicious for having cancerous change, this may require a separate procedure). Taking polyps out lowers your chances of getting cancer. Cancer screening tests are tests that are done to try and find cancer early before a person has symptoms. Cancer that is found early often is small and can be cured or treated easily.

What should I do before a colonoscopy? 

Your doctor will give you instructions about what to do before a colonoscopy. He or she will tell you what foods you can and cannot eat. He or she will also tell you if you need to stop taking any of your usual medicines beforehand.

Make sure to read the instructions as soon as you get them. You might have to stop some medicines up to a week before the test.

The colon needs to be cleaned out before a colonoscopy. Your doctor will give you a special drink that causes watery diarrhoea. It is important to drink all of it to make sure your colon is clean. If your colon is clean your doctor will get a better look at the inside lining of the colon. A clean colon also makes the test easier to do and more comfortable. Let your doctor know if you have trouble getting ready for your colonoscopy.

What happens during a colonoscopy? 

Your doctor will give you medicine to make you feel relaxed. Then he or she will put a thin tube with a camera and light on the end into your anus and up into the rectum and colon. Your doctor will inspect inside lining of the whole colon.

During the procedure, your doctor might do a test called a biopsy. During a biopsy, a doctor takes a small piece of tissue from the colon. Then he or she looks at the tissue under a microscope to see if it has cancer. Your doctor might also remove growths that he or she sees in the colon. You will not feel it if the doctor takes a biopsy or removes a growth.

What happens after a colonoscopy? 

Your doctor will give you instructions about what to do after a colonoscopy. Most people can eat as usual. But most doctors recommend that people do not drive or go to work for the rest of the day. Your doctor will tell you when to start taking any medicines you had to stop before the test.

What are other reasons my doctor might order a colonoscopy? 

Your doctor might order a colonoscopy if you have:

  • Blood in your bowel movements
  • A change in your bowel habits
  • A condition called anaemia that can make you feel tired and weak
  • Long-term belly or rectal pain that you cannot explain
  • Abnormal results from a different type of colon test
  • A history of colon cancer or polyps in your colon

When should I call my doctor or nurse? 

Call your doctor or nurse immediately if you have any of the following problems after your colonoscopy:

  • Belly pain that is much worse than gas pain or cramps
  • A bloated and hard belly
  • Vomiting
  • Fever
  • A lot of bleeding from your anus