A lower gastrointestinal (GI) series uses x rays to diagnose problems in the large intestine, which includes the colon and rectum. The lower GI series may show problems like abnormal growths, ulcers, polyps, diverticuli, and colon cancer.

Before taking x rays of your colon and rectum, the radiologist will put a thick liquid called barium into your colon. This is why a lower GI series is sometimes called a barium enema. The barium coats the lining of the colon and rectum and makes these organs, and any signs of disease in them, show up more clearly on x rays. It also helps the radiologist see the size and shape of the colon and rectum.

You may be uncomfortable during the lower GI series. The barium will cause fullness and pressure in your abdomen and will make you feel the urge to have a bowel movement. However, that rarely happens because the tube used to inject the barium has a balloon on the end of it that prevents the liquid from coming back out.

You may be asked to change positions while x rays are taken. Different positions give different views of the colon. After the radiologist is finished taking x rays, you will be able to go to the bathroom. The radiologist may also take an x ray of the empty colon afterwards.

A lower GI series takes about 1 to 2 hours. The barium may cause constipation and make your stool turn gray or white for a few days after the procedure.

Preparation

Your colon must be empty for the procedure to be accurate. To prepare for the procedure you will have to restrict your diet for a few days beforehand. For example, you might be able to drink only liquids and eat only nonsugar, nondairy foods for 2 days before the procedure; only clear liquids the day before; and nothing after midnight the night before. A liquid diet means fat-free bouillon or broth, gelatin, strained fruit juice, water, plain coffee, plain tea, or diet soda. To make sure your colon is empty, you will be given a laxative or an enema before the procedure. Your physician may give you other special instructions.

National Digestive Diseases Information Clearinghouse

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The National Digestive Diseases Information Clearinghouse (NDDIC) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The NIDDK is part of the National Institutes of Health under the U.S. Department of Health and Human Services. Established in 1980, the Clearinghouse provides information about digestive diseases to people with digestive disorders and to their families, health care professionals, and the public. The NDDIC answers inquiries, develops and distributes publications, and works closely with professional and patient organizations and Government agencies to coordinate resources about digestive diseases.

Publications produced by the Clearinghouse are carefully reviewed by both NIDDK scientists and outside experts.

This publication is not copyrighted. The Clearinghouse encourages users of this publication to duplicate and distribute as many copies as desired.

NIH Publication No. 05¨C4334
November 2004