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A colonoscopy is an exam of the lower part of the gastrointestinal tract, which is called the colon or large intestine (bowel).

Colonoscopy is a safe procedure that provides information other tests may not be able to give. Patients who require colonoscopy often have questions and concerns about the procedure.

Colonoscopy is performed by inserting a device called a colonoscope into the anus and advanced through the entire colon (See the figure).

The procedure generally takes between 10 minutes and one hour.



The most common reasons for colonoscopy are to evaluate the following:

  • As a screening exam for colon cancer
  • Rectal bleeding
  • A change in bowel habits, like persistent diarrhea
  • Iron deficiency anemia (a decrease in blood count due to loss of iron)
  • A family history of colon cancer
  • As a follow-up test in people with colon polyps or colon cancer
  • Chronic, unexplained abdominal or rectal pain
  • An abnormal X-ray exam, like a barium enema or CT scan



Before colonoscopy, your colon must be completely cleaned out so that the doctor can see any abnormal areas.

Without proper preparation the colonoscopy will not be successful and may have to be repeated.

To clean the colon, you will need to follow the prescribed diet and take a strong laxative to empty your bowels.

Your doctor’s office will provide specific instructions about how you should prepare for colonoscopy.

Be sure to read these instructions ahead of time so you will be prepared for the prep. If you have questions, contact the doctor in advance.

You will need to avoid solid food for at least one day before the test. You should also drink plenty of fluids on the day before the test.

You can drink clear liquids up to several hours before your procedure, including: Water, clear juice (apple, grape), Energade or similar alternative, clear soup (beef, chicken, or vegetable), coffee or tea (without milk) or jelly (avoid red jelly).

The day or night before the colonoscopy, you will take a laxative. It consists of a powder that is mixed with water.

The most common laxative treatment is called “Klean-Prep”. You can add some lemon squash to hide the unpleasant taste. Refrigerating the solution can make it easier to drink.

Drinking this solution may be the most unpleasant part of the exam. You will begin to have watery diarrhea within a short time after drinking the solution.

If you become nauseated or vomit while drinking the solution, call your doctor or nurse for instructions. 


You can take most prescription and non-prescription medicines right up to the day of the colonoscopy.

Your doctor should tell you what medicines to stop.
You should also tell the doctor if you are allergic to any medicines.

Some medicines increase the risk of heavy bleeding if you have a biopsy during the colonoscopy.

Ask your doctor how and when to stop these medicines, including Warfarin and Clopidogrel/Plavix®.

Transportation Home

You will be given a sedative (a medicine to help you relax) during the colonoscopy, so you will need someone to take you home after your test.

Although you will be awake by the time you go home, the sedative medicines cause changes in reflexes and judgment that can interfere with your ability to make decisions, similar to the effect of alcohol.



Before the test, a doctor will review the test, including possible complications, and will ask you to sign a consent form. The nurse or doctor will start an IV line in your hand or arm.

Your blood pressure, heart rate and oxygen levels will be monitored during the test. 


You will be given fluid and medicines through an IV line. Many people sleep during the test, while others are very relaxed, comfortable, and generally not aware.

The colonoscope is a long flexible tube, approximately the thickness of the index finger. The scope pumps air into the colon to inflate it and allow the doctor to see the entire lining.

You might feel bloating or gas cramps as the air opens the colon. Try not to be embarrassed about passing this gas, and let your doctor know if you are uncomfortable.

During the procedure, the doctor might take a biopsy (small pieces of tissue) or remove polyps.

Polyps are growths of tissue that can range in size from the tip of a pen to several centimeters.

Most polyps are benign (not cancerous). However, some polyps can become cancerous if allowed to grow for a long time. Having a polyp removed does not hurt.



After the colonoscopy, you will be observed in a recovery area until the effects of the sedative medication wear off.

The most common complaint after colonoscopy is a feeling of bloating and gas cramps. You may also feel groggy from the sedation medications. You should not return to work or drive that day.

Most people are able to eat normally after the test. Ask your doctor when it is safe to restart aspirin and other blood- thinning medications.



Colonoscopy is a safe procedure, and complications are rare but can occur:
Bleeding can occur from biopsies or the removal of polyps, but it is usually minimal and can be controlled.

The colonoscope can cause a tear or hole in the colon (also referred to as a perforation). This is a serious problem, but it does not happen commonly.

Should this happen you might need an operation to repair the tear. It is possible to have side effects from the sedative medicines.

Although colonoscopy is the best test to examine the colon, it is possible for even the most skilled
doctors to miss or overlook an abnormal area in the colon. You should call your doctor immediately if you have any of the following:

  • Severe abdominal pain (not just gas cramps)
  • A firm, bloated abdomen
  • Vomiting
  • Fever
  • Rectal bleeding (greater than a few tablespoons)



Although many people worry about being uncomfortable during a colonoscopy, most people tolerate it very well and feel fine afterward.

It is normal to feel tired afterward. Plan to take it easy and relax the rest of the day.

Your doctor can describe the results of the colonoscopy as soon as it is over.

If he took biopsies or polyps he will contact you within one to two weeks with the results.


Adapted from www.uptodate.com


The information on this website is to provide general guidance. In no way does any of the information provided reflect definitive medical advice and self-diagnoses should not be made based on information obtained online. It is important to consult a Gastroenterologist or medical doctor regarding ANY and ALL symptoms or signs including, but not limited to: abdominal pain, haemorrhoids or anal / rectal bleeding as it may a sign of a serious illness or condition. A thorough consultation and examination should ALWAYS be performed for an accurate diagnosis and treatment plan. Be sure to call a physician or call our office today and schedule a consultation.

Contact Dr Deetlefs

Room 109 Mediclinic Milnerton
Cnr Koeberg & Racecourse Roads
Cape Town
Tel: 021 551 8678

Monday – Friday: 8 AM to 4 PM

Additional address for Endoscopic Procedures:

Dr Eduan Deetlefs Inc
The Park Building, (opp, Vincent Pallotti Hospital)
Suite 304, 3rd Floor,
Park Road
Tel: 021 202 0626

Email: info @ gidoc.co.za

Vincent Pallotti Office hours:
8am to 3pm, 
Fridays:  Procedure day – in rooms scope facility 7am to 4pm.

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© Dr. Eduan Deetlefs, Registered Gastroenterologist, GI Doc Cape Town

Our website information is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. Please consult a doctor about your specific condition. Only a trained physician can determine an accurate diagnosis and proper treatment.