Procedures Colonoscopy

What is a colonoscopy?

A colonoscopy (koh-luh-NAH-skuh-pee) allows a doctor to look inside the entire large intestine. The procedure enables the physician to see things such as inflamed tissue, abnormal growths, and ulcers. It is most often used to look for early signs of cancer in the colon and rectum. It is also used to look for causes of unexplained changes in bowel habits and to evaluate symptoms like abdominal pain, rectal bleeding, and weight loss.

What is the colon?

The colon, or large bowel, is the last portion of your digestive tract, or gastrointestinal tract. The colon is a hollow tube that starts at the end of the small intestine and ends at the rectum and anus. The colon is about 5 feet in length and its main function is to store unabsorbed food waste and absorb water and other body fluids before the waste is passed as stool.


You will be given instructions in advance that will explain what you need to do to prepare for your colonoscopy. Your colon must be completely empty for the colonoscopy to be thorough and safe. To prepare for the procedure you will have to follow a liquid diet for 1 to 3 days prior to the procedure. The liquid diet should be clear and not contain red or purple food colorings or dies, but may include but not limited to the following:

  • fat-free bouillon or broth
  • strained fruit juice
  • water
  • black coffee, no creamer or sugar
  • plain tea, no sweeteners
  • soda (clear)
  • gelatin

Thorough cleansing of the bowel is absolutely necessary before a colonoscopy. You may be asked to take a laxative the night before the procedure. In some cases you may be asked to give yourself an enema. An enema is performed by inserting a bottle with water and sometimes a mild soap in your anus to clean out the bowels.

The medical staff will need to know if you have heart disease, lung disease, or any medical condition that may need special attention. Be sure to inform your doctor of any medical conditions you have or medications you take on a regular basis, including, but not limited to:

  • aspirin
  • arthritis medications
  • blood thinners
  • diabetes medication
  • vitamins that contain iron

You must also arrange for someone to take you home after your procedure. The sedatives you will receive during you procedure will inhibit your ability to drive and can also make you extremely drowsy.


For the colonoscopy, once you are in the procedure room you will lie on your left side on the examining table. You will be given pain medication and a moderate sedative to keep you comfortable and help you relax during the exam. The physician and a nurse will monitor your vital signs, look for any signs of discomfort, and make adjustments as needed throughout the procedure.

Once you are comfortable the doctor will then insert a colonoscope (koh-LON-oh-skope which is a long, flexible, lighted tube into your rectum and slowly guide it into your colon. The scope transmits an image of the inside of the colon onto a video screen so the doctor can carefully examine the lining of the colon.

The colonscope is also used to inflate the colon with air so the doctor can thoroughly examine the entire lining of the colon.  Also, during the procedure the physician is able to remover polyps (an abnormal grown in the lining of the bowl) and take biopsies by using very small tools passed through the scope.

Even though most polyps are benign (not cancerous) the doctor is unable to identify whether or not the polyps is cancerous just by looking at them. So, when the polyps are removed they are sent to the lab for testing. By taking tissue samples of the colon (biopsy) the physician is able to test for other disease of the colon without the need for a major operation.

During the procedure you may feel mild cramping. You can reduce the cramping by taking several slow, deep breaths. When the doctor has finished, the colonoscope is slowly withdrawn while the lining of your bowel is carefully examined. Bleeding and puncture of the colon are possible but uncommon complications of a colonoscopy. Most patients do not remember the procedure because of the sedatives given during the procedure.

Post Procedure

Read your discharge instructions completely and carefully. Typically you are expected to return to your regular activities the day after your procedure. Unless otherwise directed by your physician. Medications such as blood-thinners may need to be stopped for a short time after having your colonoscopy, especially if a biopsy was performed or polyps were removed.

Rarely, some people experience severe abdominal pain, fever, bloody bowel movements, dizziness, or weakness after their procedure. If you have any of these side effects, contact your physician immediately.

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