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Flexible Sigmoidoscopy


We offer Flexible Sigmoidoscopy at both our Credit Valley Hospital and Mississauga Hospital locations.

Flexible Sigmoidoscopy is a test where a doctor passes a flexible tube about the thickness of your finger into your anus and slowly advances it into your rectum and the lower part of your colon. This procedure allows the doctor to:

  • examine the lining of the rectum and a portion of the colon (large intestine)

Flexible Sigmoidoscopy can be used to diagnose:

  • ulcers
  • abnormal cells
  • polyps
  • cancer


A referral from a doctor is required.

Resources for Patients & Their Families

How to Prepare for Flexible Sigmoidoscopy

Your doctor will tell you what you need to do. It is common for patients to prepare by taking the following, which you can buy at your local pharmacy without a prescription:

Dulcolax - Four (4) Tablets
And Magnesium Citrate – 1 bottle

You must take exactly what your doctor tells you to and not make any substitutions.
If Your Appointment is in the Morning (before 12:00 pm):
Take the preparation the night before. Once you start your preparation only consume clear fluids such as tea, black coffee, juice. Do not eat solid food after starting your laxative. You may have clear fluids up to 2 hours prior to your appointment time.

If Your Appointment is in the Afternoon (after 12:00 pm):
Take the preparation 6 hours before your appointment. Once you start your preparation only consume clear fluids such as tea, black coffee, juice. Do not eat solid food after starting your laxative. You may have clear fluids up to 2 hours before your appointment time.

Make sure you have finished your laxatives 4 hours before your test.

Should I Continue Taking My Current Medications?

Most medications can be continued as usual. Tell your doctor about medications that you're taking, particularly aspirin products or anticoagulants (blood thinners such as warfarin or heparin), or clopidogrel. Also make sure you let your doctor know about any allergies you have to medications.

What to Expect During Flexible Sigmoidoscopy

You will lie on your side while your doctor passes the sigmoidoscope through your rectum and colon. You might experience a feeling of pressure, bloating or cramping during the procedure. As your doctor removes the instrument, your doctor will carefully examine the lining of your intestine.

What if the Flexible Sigmoidoscopy Finds Something Abnormal?

If your doctor sees an area that needs further evaluation, your doctor might take a biopsy (tissue sample) to be analyzed. Obtaining a biopsy does not cause any pain or discomfort. Biopsies are used to identify many conditions, and your doctor might order one even if he or she doesn't suspect cancer.

Your doctor might also take a biopsy if he or she finds polyps. There are different types and sizes of polyps, which are growths from the lining of the colon. Polyps known as "hyperplastic" might not need to be taken out, but benign polyps known as "adenomas" have a small risk of becoming cancerous. Your doctor will likely ask you to have a colonoscopy (a complete examination of the colon) to remove any large polyps or any small adenomas.

What Happens After a Flexible Sigmoidoscopy?

Your doctor will explain the results to you when the procedure is done. You might feel bloating or some mild cramping because of the air that was passed into your colon during the examination. This will disappear quickly when you pass gas. You should be able to eat and resume your normal activities after leaving your doctor's office or the hospital, assuming you did not receive any sedative medication.

Are There Any Possible Complications?

Complications are rare, but it is important for you to recognize the early signs of possible complications. Contact your doctor if you notice:

  • severe abdominal pain
  • fevers and chills
  • rectal bleeding. (Note that rectal bleeding can happen several days after the test.)