Lower GI Endoscopy

Lower GI endoscopy allows your doctor to view your lower gastrointestinal (GI) tract. Your entire colon and rectum can be examined (colonoscopy). Or just the rectum and sigmoid colon can be examined (sigmoidoscopy).

Outline of torso showing colon, sigmoid colon, and rectum. Scope is inserted through rectum and sigmoid colon into middle of colon.
During endoscopy, a long, flexible tube is used to view the inside of your lower GI tract.

Before the exam

Follow these and any other instructions you are given before your endoscopy. If you don’t follow the doctor’s instructions carefully, the test may need to be cancelled or done over.

  • For a colonoscopy, you may be told not to eat and to drink only clear liquids for one to three days before the exam.

  • Take any laxatives that are prescribed for you. An enema may also be prescribed.

  • Arrange for someone to drive you home after the exam if you will be sedated.

  • Tell your health care provider before the exam if you are taking any medications, vitamins, supplements, or have any medical problems.

When to call your doctor

Call if you have any of the following after the procedure:

  • Pain in your abdomen

  • Fever

  • Rectal bleeding

The procedure

  • Colonoscopy can take 30 minutes or longer. Sigmoidoscopy often takes about 20 minutes.

  • You lie on the stretchr or bed on your left side.

  • For colonoscopy, you are given sedating (relaxing) medication through an IV line. Sigmoidoscopy usually doesn’t require sedation.

  • The endoscope is inserted into your rectum. You may feel pressure and cramping. If you feel pain, tell your doctor or nurse. You may receive more sedation which includes pain medication and an anti-anxiety medication. 

  • The endoscope carries images of your colon to a video screen. Prints of the images may be taken as a record of your exam.

  • When the procedure is done, you rest for a time. You may have some discomfort right after the procedure from trapped air. This can be relieved by changing position and passing the air. If you have been sedated, you must have an adult drive you home.

Online Medical Reviewer: Larson, Kim, APRN, FNP
Online Medical Reviewer: MMI board-certified, academically affiliated clinician
Last Review Date: 3/30/2014
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