Lower GI Series

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What is lower gastrointestinal (GI) series?

A lower GI series is a procedure in which a doctor uses x-rays and a chalky liquid called barium to view your large intestine. The barium will make your large intestine more visible on an x-ray.

The two types of lower GI series are

  • a single-contrast lower GI series, which uses only barium
  • a double-contrast or air-contrast lower GI series, which uses both barium and air for a clearer view of your large intestine

Does lower GI series have another name?

A lower GI series is also called a barium enema.

Why do doctors use lower GI series?

A lower GI series can help a doctor find the cause of

A lower GI series can also show

How do I prepare for a lower GI series?

To prepare for a lower GI series, you will need to talk with your doctor, change your diet, and clean out your bowel.

Talk with your doctor

You should talk with your doctor about any medical conditions you have and all prescribed and over-the-counter medicines, vitamins, and supplements you take.

Also tell your doctor whether you’ve had a colonoscopy with a biopsy or polyp removal in the last 4 weeks.

Doctors don’t recommend x-rays for pregnant women because x-rays may harm the fetus. Tell your doctor if you are, or may be, pregnant. Your doctor may suggest a different procedure.

Change your diet and clean out your bowel

A health care professional will give you written bowel prep instructions to follow at home before the procedure. A health care professional orders a bowel prep so that little to no stool is present in your intestine. A complete bowel prep lets you pass stool that is clear and liquid. Stool inside your colon can prevent the x-ray machine from taking clear images of your intestine.

You may need to follow a clear liquid diet for 1 to 3 days before the procedure. The instructions will provide specific direction about when to start and stop the clear liquid diet. In most cases, you may drink or eat the following:

  • fat-free bouillon or broth
  • gelatin in flavors such as lemon, lime, or orange
  • plain coffee or tea, without cream or milk
  • sports drinks in flavors such as lemon, lime, or orange
  • strained fruit juice, such as apple or white grape—doctors recommend avoiding orange juice
  • water
White woman with blonde hair drinking a glass of water.
You may need to follow a clear liquid diet for
1 to 3 days before a lower gastrointestinal (GI) series.

Your doctor will tell you how long before the procedure you should have nothing by mouth.

A health care professional will ask you to follow the directions for a bowel prep before the procedure. The bowel prep will cause diarrhea, so you should stay close to a bathroom.

Different bowel preps may contain different combinations of laxatives—pills that you swallow or powders that you dissolve in water and other clear liquids—and enemas. Some people will need to drink a large amount, often a gallon, of liquid laxative during a scheduled amount of time—most often the night before the procedure.

You may find this part of the bowel prep difficult; however, completing the prep is very important. Your doctor will not be able to see your large intestine clearly if the prep is incomplete.

Call a health care professional if you have side effects that prevent you from finishing the prep.

How do doctors perform a lower GI series?

An x-ray technician and a radiologist perform a lower GI series at a hospital or an outpatient center. You do not need anesthesia. The procedure usually takes 30 to 60 minutes.

For the procedure, you’ll be asked to lie on a table while the radiologist inserts a flexible tube into your anus and fills your large intestine with barium. The radiologist prevents barium from leaking from your anus by inflating a balloon on the end of the tube. You may be asked to change position several times to evenly coat the large intestine with the barium. If you are having a double-contrast lower GI series, the radiologist will inject air through the tube to inflate the large intestine.

During the procedure, you may have some discomfort and feel the urge to have a bowel movement. You will need to hold still in various positions while the radiologist and technician take x-ray images and possibly an x-ray video, called fluoroscopy.

The radiologist or technician will deflate the balloon on the tube when the imaging is complete. Most of the barium will drain through the tube. You will push out the remaining barium into a bedpan or nearby toilet. A health care professional may give you an enema to flush out the rest of the barium.

Male healthcare provider in white lab coat holding a clipboard talking with a female patient.
An x-ray technician and a radiologist perform a lower
gastrointestinal (GI) series at a hospital or an outpatient center.

What should I expect after a lower GI series?

After a lower GI series, you can expect the following:

  • You may have cramping in your abdomen and bloating during the first hour after the procedure.
  • You may resume most normal activities after leaving the hospital or outpatient
  • For several days, your stools may be white or light colored from the barium in your large intestine.
  • A health care professional will give you instructions on how to care for yourself after the procedure. The instructions will explain how to flush the remaining barium from your large intestine. You should follow all instructions.

The radiologist will read the x-rays and send a report of the findings to your doctor.

What are the risks of a lower GI series?

The risks of a lower GI series include

  • constipation from the barium enema—the most common complication of a lower GI series
  • an allergic reaction to the barium
  • intestinal obstruction
  • leakage of barium into your abdomen through a tear or hole in the lining of the large intestine
Last Reviewed June 2016
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This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. NIDDK translates and disseminates research findings to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by NIDDK is carefully reviewed by NIDDK scientists and other experts.