What is a colonoscopy?

A colonoscopy is a procedure in which a doctor uses a colonoscope or scope, to look inside your rectum and colon. A colonoscopy can show irritated and swollen tissue, ulcers, polyps, and cancer.

Why do doctors use colonoscopy?

A colonoscopy can help a doctor find the cause of symptoms, such as:

• bleeding from your anus

• changes in your bowel activity, such as constant diarrhea and change in stool shape

• pain in your abdomen

 unexplained weight loss

You have risk factors for colorectal cancer if:

• You or someone in your family has had colorectal cancer.

• You have a personal history of inflammatory bowel disease, such as Ulcerative Colitis and Crohn’s disease.

• You have HNPCC (hereditary nonpolyposis colorectal cancer) , or another genetic disorder that increases the risk of colorectal cancer.

If you are more at risk to develop colorectal cancer, your doctor may recommend starting screening at a younger age, and more frequently.  For more information regarding screening, refer to “Screening for Colorectal Cancer” under the  “patient education” tab.

How do I prepare for a colonoscopy?

To prepare for a colonoscopy, refer to the bottom of this page and use the prep form that your surgeon has indicated for you to use.
The bowel prep will cause diarrhea, so you should stay close to a bathroom. You may find this part of the bowel prep hard however, finishing the prep is very important to obtain excellent prep results.



Speak with your doctor.

You should speak with your doctor about any health problems that you have and all prescribed and over-the-counter medicines, vitamins, and supplements you take such as:

• aspirin or medicines that contain aspirin

• blood thinners/ anti-coagulants

•  herbal supplements or vitamins that contain iron

How do doctors perform a colonoscopy?

The colonoscopy procedure is done in a day surgery setting (TBRHSC’s- 3rd Floor Endoscopy Unit).  A colonoscopy usually takes 30 to 60 minutes but may vary with each patient.

The doctor will place an intravenous (IV) needle in a vein in your arm or hand to give you sedatives, anesthesia, or pain medicine, so you won’t be aware or feel pain during the procedure. The health care staff will check your vital signs and keep you as comfortable as possible.

For the procedure, you’ll lie on a table while the doctor inserts a colonoscope through your anus and into your rectum and colon. The scope inflates your large intestine with air for a better view. The camera sends a video image to a monitor, allowing the doctor to examine your large intestine.

The doctor may move you several times on the table to adjust the scope for better viewing. Once the scope reaches the opening to your small intestine, the doctor slowly removes the scope and examines the lining of your large intestine again.

During the procedure, the doctor may remove polyps and will send them to a lab for testing. You will not feel the polyp removal. Colon polyps are common in adults and are harmless in most cases. However, most colon cancer begins as a polyp, so removing polyps early helps to prevent cancer.

If your doctor finds abnormal tissue, a biopsy may be taken. You won’t feel the biopsy. If the doctor removed polyps or performed a biopsy, you may have light bleeding from your anus. This bleeding is normal. A pathologist will examine the biopsy tissue once the results become available your surgeon’s office will contact you or schedule an appointment to go over the results.

What should I expect after a colonoscopy?

After a colonoscopy, you can expect the following:

• The anesthesia takes time to wear off completely. You’ll stay at the hospital or outpatient center for 1 to 2 hours after the procedure for observation.

• You may feel cramping in your abdomen or bloating during the first hour after the procedure.

• After the procedure, you or a friend or family member—will receive instructions on how to care for yourself after the procedure. 

• You’ll need your pre-arranged ride home, since you won’t be able to drive after the procedure.

• After the sedatives or anesthesia wear off, your doctor may share what was found during the procedure with you, and if you choose a family member or friend.

What are the risks of colonoscopy?

The risks of colonoscopy include:

• bleeding

• perforation of the colon

• a reaction to the sedative, including breathing or heart problems

• severe pain in your abdomen

Seek care right away.

If you have any of the following symptoms after a colonoscopy, seek medical care right away:

• severe pain in your abdomen

• fever

• bloody bowel movements that do not get better

 bleeding from the anus that does not stop

• dizziness

• weakness

Click below on the specific colonoscopy instructions that your surgeon has indicated for you to use:

Colonoscopy with Pico Salax prep

Colonoscopy with PegLyte prep

Colonoscopy and Gastroscopy prep



• In 2013, 8,759 cases of colorectal cancer were diagnosed in Ontario, making it the 3rd most common cancer. There were also 3,030 colorectal cancer deaths, making it the 2nd leading cause of cancer death.

• One in 14 Ontarians is expected to be diagnosed with colorectal cancer in their lifetime, and 1 in 31 is expected to die from it.

• Survival for colorectal cancer is average compared to other cancers. People diagnosed with colorectal cancer are 66.7% as likely to survive 5 years after diagnosis compared to similar people in the general population.