What is a Colonoscopy?

What is a Colonoscopy?

COLONOSCOPY: Examination of the Large Intestine and Rectum

Colonoscopy is a procedure that is performed by using a colonoscope – a flexible, long, narrow tube with a tiny camera and light to look inside the colon or large intestine and the rectum. This procedure can reveal problems inside the intestine such as swelling, irritation, masses, ulcer, or polyps, which is a tissue malformation that grows anywhere within the lining of the intestine.


Colonoscopy is usually done by a gastroenterologist – a doctor who specializes in diseases and problems in the digestive system.

It is performed to assess and identify the cause of problems such as:

  • Abdominal pain
  • Extreme weight loss
  • Bleeding from bowel
  • Unexplained changes in bowel habits

A colonoscopy is also used for colon cancer screening. It may help diagnose cancer, especially on the early stage when there is a better chance of intervening and curing the disease.


Your doctor will give you instructions on how to prepare a few days before your colonoscopy. It is essential that the colon is clean for the procedure so that the doctor can see important markers.

To prepare for your colonoscopy and prepare your bowel, you must:

Talk to your doctor.

As with other procedures, it would be necessary for you to talk to your doctor with regards to any allergies, medical conditions you have, and if you are taking vitamins, supplements or other prescribed medications.

Change your diet.

  • Two days before your colonoscopy, you may be advised by your doctor to be on a low fibre diet.
  • One day before, you will be asked not to eat any solid food.

Increase your fluid intake.

  • You will be advised to considerably increase your water or fluid intake two days before the procedure while you are on a low fiber diet.
  • One day before, your liquid intake should be clear fluids only like clear soups, fruit jelly, or tea.

Take the prescribed bowel preparation medication. 

You may be given a laxative medication to flush the colon for it to be free of stool.

Arrange for a drive home after the procedure. 

Talk to someone to drive you home on the day of the procedure because driving won’t be allowed for 24 hours after colonoscopy.


A colonoscopy procedure may be divided into two or three parts:

Introduction of Anesthesia

To start the procedure, a sedative (light anesthesia) is usually given.
You may be slightly aware, but you won’t know the entire process in detail.

The staff will make you feel as comfortable as possible. Your vital signs will be monitored during the whole procedure which may take about 20 to 45 minutes.

Examination of the Bowel

Once the anesthesia takes effect, and you are positioned on your left side, the colonoscope will be inserted through your anus towards your colon. The camera on the colonoscope will transmit a video image of the insides of your colon, to allow your doctor to examine the condition of your intestinal lining.

Once it reaches the small intestine’s opening, the colonoscope is slowly withdrawn, and the large intestine’s surface is carefully examined again.

Removal of Polyps, Tissue Samples or Biopsy

If polyps (small tissue growth attached to the lining of the bowel) are found during the colonoscopy, your doctor might remove them using specialized tools. These polyps may be harmless, but as a precaution and to prevent cancer, they are typically removed.

Small tissue samples may also be taken for biopsy to be examined thoroughly. This will allow your doctor to inspect it completely using a microscope in the laboratory for any signs of disease.


Immediately after the procedure, you will be transferred to the recovery room for monitoring. You will remain there for 1 to 2 hours until the anesthetic medication wears off.

When you wake up, it is normal to feel a little bloated due to the air that moved into your colon during the procedure, which will pass over in the next hour or two. You may be given a drink or light meal if you feel hungry.

Due to the anesthesia administered during your colonoscopy, it is strongly advised that you do not drive, ride on public transport alone, operate on any machinery, drink alcohol, or sign legal documents on the same day after the procedure. Also, have someone to stay at home with you.

After 24 hours, full recovery is expected. Follow the discharge instructions given by your physician.


Complications may occur, but they are rare and only very few people experience side-effects.
After the procedure, some people feel bloated. If a polyp was removed or a small tissue was taken, there might be minor bleeding. In some rare situations, the bowel lining may be injured or torn which will be repaired by the doctor. Reactions to the anesthesia are also possible, but like an injury to the stomach, it is very rare.

To know more about the benefits, risks, side-effects and other specific details on colonoscopy, book an appointment with your physician or call us at 214-231-CARE (2273). You can read more about Pine Creek Medical Center’s gastroenterology department for more info.



• “Colonoscopy.” San Francisco Surgery | General Surgery, Colorectal, Laparoscopic and Endocrine. National Institute of Diabetes and Digestive and Kidney Diseases (, Web. <http://sfsurgery.com/wp-content/uploads/2014/06/Colonoscopy.pdf>.

• “Colonoscopy.” American College of Surgeons. Division of Education. Colonoscopy, Web. <http://www.facs.org/~/media/files/education/patient%20ed/colonoscopy.ashx>.

• “Information about Colonoscopy.” Gastroenterological Society of Australia (GESA),. Digestive Health Foundation, Web. <http://cart.gesa.org.au/membes/files/Consumer%20Information/Colonoscopy.pdf>.