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Learning About Colonoscopy

Normal colon and colon polyp

What is a colonoscopy?

A colonoscopy is a test (also called a procedure) that lets a doctor look inside your large intestine. The doctor uses a thin, lighted tube called a colonoscope. The doctor uses it to look for small growths called polyps, colon or rectal cancer (colorectal cancer), or other problems like bleeding.

During the procedure, the doctor can take samples of tissue. The samples can then be checked for cancer or other conditions. The doctor can also take out polyps.

How is colonoscopy done?

This procedure is done in a clinic or hospital. You may choose if you want to have sedation medicine to help you relax. A colonoscopy can be comfortable without sedation. Some people get cramps (pain). Many people do choose to have sedation for the test. Some people find that they do not remember very much about the test because of the sedation medicine.

The doctor gently moves the colonoscope, or scope, through the colon. The scope is also a small video camera. It lets the doctor see the colon and take pictures.

A colonoscopy usually takes 30 to 45 minutes. It may take longer if the doctor has to remove polyps.

How do you prepare for the procedure?

You need to clean out your colon before the procedure so the doctor can see all of your colon. You may start the cleaning process a day or two before the test. This depends on which "colon prep" your doctor recommends.

To clean your colon, you stop eating solid foods and drink only clear liquids. You can have water, tea, coffee, clear juices, clear broths, flavoured ice pops, and gelatin (such as Jell-O). Do not drink anything red, purple, or blue, such as grape juice or fruit punch. And do not eat red, purple, or blue foods, such as grape ice pops or cherry gelatin.

To clean out your colon you will need to follow a special diet and drink a large amount of a bowel preparation (laxative) solution. This causes loose, frequent stools. You will go to the washroom a lot. It is very important to drink all of the colon prep liquid. If you have problems drinking the liquid, call your doctor or nurse call line.

For many people, the prep is worse than the test. It may be uncomfortable, and you may feel hungry on the clear liquid diet. Some people do not go to work or do their usual activities on the day of the prep.

Arrange to have someone take you home after the test.

What can you expect after a colonoscopy?

The nurses will watch you for 1 to 2 hours until the medicines wear off. Then you can go home. You will need a ride if you get sedation medicine. After your test you can start to eat your usual diet, unless your doctor gives you other instructions. Avoid any activity that takes a lot of energy like hard exercise or heavy lifting. Your healthcare team will talk to you about when you can go back to your usual activity.

Your doctor will talk to you about when you will need your next colonoscopy. The results of your test and your risk for colorectal cancer will help your doctor decide how often you need to be checked.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse call line if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

When should you call for help after your procedure?


Call 911 anytime you think you may need emergency care. For example, call if:
  • you passed out (lost consciousness) or feel like you will faint
  • you pass a lot of blood from your rectum
  • you have trouble breathing
Call your doctor, nurse call line, or seek immediate medical care if:
  • you have pain that does not get better even after passing gas
  • you are sick to your stomach or cannot drink fluids
  • you have new or worse belly pain
  • you have blood in your stools
  • you have a fever (over 38°C or 100.4°F)
  • you cannot pass stools or gas
Watch closely for changes in your health, and contact your doctor or nurse call line (811 in Alberta) if you have any problems or questions.

Where can you learn more?

Go to https://www.healthwise.net/patientEd

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