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Colonoscopy Explained

Ontario Colonoscopy Clinics performs 3 types of procedures:

colonoscopy example


polyp removal

Polypectomy (removal of a polyp)



Patients will need to prepare for those procedures according to the instructions provided by the doctors and staff when booking their appointment. More information on the preparation can be found below, or downloaded here.

About the Colonoscopy

A colonoscopy is a direct visual examination of the entire large intestine or colon. The colonoscope, a specialized piece of equipment, is inserted into the rectum and maneuvered through the full length of the colon. The scope is over one meter long and about the width of a finger. Images from the scope are transmitted to a video monitor that your doctor uses to inspect the lining of the bowel. If any abnormalities are found, pictures and biopsies can be taken, as small pieces of tissue can be removed during the procedure.

You will need to clean out or prepare the bowel prior to the procedure. To view the complete, printable version of the preparation instructions. More information on the preparation can be found below, or downloaded here.

Sedation is given for the procedure; therefore, you will need to arrange for someone else to drive you home.

The colonoscopy is a very safe procedure, but as with any invasive test, there are some risks. A perforation or hole in the bowel is made in less than 1 in 3000 cases. If this occurs, surgery may be required to repair the bowel. The likelihood of detecting a colon polyp or a colon cancer is much higher than the chance of a perforation.

About the Polypectomy
or Polyp Removal

Polyps are small, mushroom shaped growths that form on the inner lining of the colon. If left alone, some polyps will continue to grow in size and can develop into colon cancer. If a polyp is seen during your colonoscopy, your doctor will use a thin wire snare to lasso and remove it. The polyp can then be retrieved and sent for microscopic evaluation. Your doctor will ask you for a follow-up at the office to discuss the results.

About the Gastroscopy

A gastroscopy is a direct visual examination of the upper intestinal tract (esophagus, stomach and duodenum). During your visit to Ontario Colonoscopy Clinics, your doctor may suggest a gastroscopy if you have upper intestinal symptoms such as indigestion and heart burn, or if you have signs of possible upper intestinal bleeding such as anemia (low blood count), or a positive fecal blood test. Pictures and biopsies can be taken during a gastroscopy.

Preparing for your Colonoscopy


  • If you are on blood thinners (Coumadin, Warfarin Plavix, Aspirin, Xarelto), please consult your family doctor or surgeon for instructions on number of days prior to procedure for stopping these medications.
  • If you are Diabetic, please discuss with your family doctor or surgeon, as your medications may need to be adjusted prior to your procedure.


3 days before colonoscopy:

  • Stay on a low fiber diet. Do not eat beans, corn, tomatoes, cucumbers, nuts, or any food containing seeds such as poppy, sesame, or sunflower. Stop green leafy vegetables/lettuce.
  • You will need to purchase a Bi-Peglyte bowel preparation kit (kit contains 2 sachets of Bi-Peglyte powder plus 3 bisacodyl tablets). This can be purchased from our clinic or from any pharmacy without a prescription


The day before colonoscopy:

Starting on the day BEFORE your procedure and until AFTER your procedure: NO SOLID FOOD. DRINK ONLY clear fluids such as: water, apple juice, white grape juice (clear, no pulp, NO RED JUICE), JELL-O, gelatin (clear, NO RED JELL-O/gelatin), black coffee/tea (no milk or dairy), Gatorade (clear is best, NO RED), clear broth (nothing in it – no noodles, no vegetables, etc.), popsicles/freezies (NO RED), ginger ale or sprite. Drink at least a glass of clear fluid every waking hour, as this will help clear and empty your colon and keep you hydrated. NO SOLID FOOD OR DAIRY PRODUCTS, and no red drinks.


Bi-Peglyte preparation (do this the morning before your colonoscopy):

  1. To prepare the Bi-Peglyte solution, mix the contents of one sachet with 1 litre of water. Mix thoroughly. Repeat with the second sachet. You will now have TWO LITRES of Bi-Peglyte solution. Put the two litres of solution in the fridge to chill.
  2. Make sure to drink a variety and lots of clear fluids the day before the procedure, and the day of the procedure, up until 3 hours before your procedure: at least a glassful every waking hour.


Instructions for taking the Bi-Peglyte bowel preparation. 4 STEPS:

  1. At 2PM (day before): Take the 3 bisacodyl tablets with a glass of water.
  2. At 8PM (evening before): Drink the first litre of Bi-Peglyte at 8PM. Drink a glassful every 10-15 minutes until finished the full litre.
  3. At 4 hours before your colonoscopy, (morning of your colonoscopy) drink the second litre of Bi-Peglyte. Drink a glassful every 10-15 minutes until finished full litre.
  4. You can continue to drink clear fluids up until 3 HOURS BEFORE your procedure.

Special instructions for the day of the procedure:

  • If approved by your doctor, you may take your usual medications today, with a small sip of water.
  • You will need a responsible driver to drive you home and a responsible adult to receive you. If you do not have such a person, you will risk cancellation of your procedure. No driving yourself for 24 hours post-procedure.