Understanding Upper Endoscopy and Colonoscopy

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What is endoscopy?

Endoscopy is a procedure in which the gastro-intestinal tract (GI tract) is viewed through a lighted, flexible tube with a camera at the end (endoscope). Small samples of tissues cells (biopsy) can also be collected and sent for testing.

There are two basic types of endoscopy:

  1. Upper endoscopy – The esophagus, stomach, and small intestines can be viewed by a thin flexible tube inserted through the mouth.
  2. Colonoscopy – The lining of the large intestine, colon and rectum can be viewed by a flexible tube inserted through the rectum.


  • Blood tests are sometimes required.
  • Medications can be given by vein if needed.
  • Please arrange for a ride home. You may feel drowsy after the procedure due to medications.
  • Upper endoscopy: No food or drink is allowed for six hours before the procedure. An empty stomach allows for the best view and safest exam.
  • Colonoscopy: Drink only clear liquids for at least 24 hours before the procedure. A laxative or special cleansing solution will be ordered by the physician to clear the bowel of stool so that the rectum/intestines can be seen. (See below for specific instructions)

Day of Procedure

  • The doctor will explain the procedure and get your consent.
  • Tell your doctor about medications you are taking.
  • Discuss allergies to medications and other medical conditions.
  • This is the time to ask questions about procedure.

What can I expect during upper endoscopy?

Your doctor will spray your throat with a local anesthetic or give you a sedative to help you relax. You’ll then lie on your side, and a doctor will pass the endoscope through your mouth and into the esophagus, stomach and duodenum. The endoscope doesn’t interfere with your breathing. Most patients consider the test only slightly uncomfortable, and many patients fall asleep during the procedure.

What happens after upper endoscopy?

You will be observed closely until most of the effects of the medication have worn off. Your throat might be a little sore, and you might feel temporarily bloated due to the air introduced into your stomach during the test. You will be able to eat after you leave unless your doctor instructs you otherwise.

Your doctor generally can tell you your test results on the day of the procedure; however, the results of some tests might take several days.

If you received sedatives, you won’t be allowed to drive after the procedure even though you might not feel tired. You should arrange for someone to accompany you home because the sedatives may affect your judgment and reflexes for the rest of the day.

What happens during colonoscopy?

Colonoscopy is well-tolerated and rarely causes much pain. You might feel pressure, bloating or cramping during the procedure. You will likely receive a sedative to help you relax and better tolerate any discomfort.

You will lie on your side or back while your doctor slowly advances a flexible tube (colonoscope) through your large intestine to examine the lining. The whole procedure itself usually takes 45 to 60 minutes, although you should plan on two to three hours for waiting, preparation and recovery.

What happens after a colonoscopy?

Your physician will explain the results of the examination to you, although you’ll have to wait for the results of any biopsies performed. If you were given sedatives during the procedure, someone must drive you home and stay with you. Even if you feel alert after the procedure, your judgment and reflexes could be slow for the rest of the day. You may have some cramping or bloating because of the air introduced into the colon during the examination. This should disappear quickly when you pass gas.

You should be able to eat after the examination, but your doctor may restrict your diet and activities, especially after the removal of any polyps.