What Is a Barium Enema?

Sometimes a doctor needs a clearer outline of the large bowel — the colon and rectum — than symptoms alone can give. A barium enema is one of the older, well-established ways of getting that outline. It is an X-ray examination of the lower gastrointestinal tract: a white liquid containing barium is passed gently into the bowel through the rectum, the barium coats the inner lining, and X-ray images then show the shape and contours of the colon in detail that a plain X-ray cannot.

The short video at the top of this page, titled simply "Barium Enema", shows the examination itself in just over four minutes. The steps below follow the order you would actually meet them — why the test is ordered, how you prepare, what happens in the X-ray room, and what comes afterwards.

Step one: why this test is ordered

A barium enema is usually requested when a clinician wants to look at the structure of the large bowel — its width, its contours, and anything that changes its outline. Changes in bowel habit, unexplained abdominal discomfort, or blood in the stool are among the reasons a lower bowel examination may be suggested, and this test can show areas of narrowing, pouches pushing out from the bowel wall, growths projecting into the bowel, and other changes in shape that deserve a closer look. It sits alongside, rather than instead of, looking directly inside the bowel: our colonoscopy hub explains the camera examination, and if you want to see that test in action, the video "Colonoscopy" shows the scope examination of the same part of the body. The two tests answer overlapping questions in different ways — one maps the outline, the other views the lining directly and can take samples.

Step two: preparing the bowel

Preparation matters more for this test than for most X-rays, for a simple reason: anything left inside the bowel can hide the very outline the pictures are meant to show, or imitate an abnormality that is not really there. So the bowel needs to be as empty as possible beforehand. In practice that usually means a period of eating lightly or taking only fluids, and a laxative preparation the day before, following the written instructions your own department gives you — preparations vary, and the leaflet that comes with your appointment is the one to follow. Tell the team in advance about any medicines you take, any allergies, and any possibility of pregnancy, because X-ray examinations are approached with extra care in pregnancy and the team will want to plan accordingly.

Step three: the examination itself

In the X-ray room you lie on an examination table, and a small, soft tube is passed a short way into the rectum. The barium liquid flows through that tube and gradually fills the large bowel. The radiologist or radiographer follows its progress on a screen using fluoroscopy — moving X-ray images — and a series of still pictures is taken as the barium coats different sections. You will be asked to roll from side to side, and sometimes onto your front or back, so the liquid coats the whole lining and each part of the colon is pictured. In some examinations a small amount of air is added after the barium, which stretches the bowel slightly and gives a sharper contrast between the coated wall and the air inside; you may hear this called a double-contrast study.

Most people describe the test as uncomfortable rather than painful. A full, crampy feeling and a strong urge to go to the toilet while the bowel is filled are commonly described, and passing the tube and holding the liquid in take a little concentration. Breathing slowly and telling the team if cramping builds helps — they are used to it, and they work as quickly as the pictures allow. Children having the test are handled with extra support from the team and a parent or carer close by.

Step four: afterwards, and what the pictures can show

Once enough images have been taken, the tube is removed and you can go straight to the toilet to pass the barium. Your stool may look pale or white for a day or two afterwards — that is simply the barium leaving. Drinking plenty of fluids afterwards is the usual advice, because barium left sitting in the bowel can firm up and contribute to constipation. The images are then studied by a specialist, who reports on the outline and contours of the colon: whether its width looks even, whether anything narrows it, pouches from it, or projects into it. A growth projecting into the bowel, for example, is the kind of finding discussed in our guide to colon polyps, and a barium study that raises a question is normally followed by a direct examination rather than treated as a final answer on its own.

Two honest limitations are worth knowing. First, a barium enema shows shape, not surface detail: small or flat changes in the lining can be missed, which is one reason colonoscopy is often chosen when the lining itself needs inspecting. Second, the test cannot take tissue samples, so anything it finds that needs identifying still requires another procedure. Where cancer of the large bowel is part of the wider picture being investigated, our article on colorectal cancer explains how the different examinations fit together. None of this makes the barium enema obsolete — it remains a useful map of the bowel, particularly when a camera examination is not possible or when the overall shape and length of the colon is the question being asked.

References & further reading

- MedlinePlus — Barium enema: https://medlineplus.gov/ency/article/003817.htm

- Johns Hopkins Medicine — Barium Enema: https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/barium-enema

- RadiologyInfo.org — Lower GI X-ray (Barium Enema): https://www.radiologyinfo.org/en/info/lowergi

Frequently Asked Questions

Does a barium enema hurt? Most people describe discomfort rather than pain — a full, crampy feeling and an urge to go to the toilet while the bowel is filled with barium. The team expects this, works as quickly as the pictures allow, and will tell you how to signal if you need a pause.

How do I prepare for a barium enema? The bowel must be as empty as possible, which usually means eating lightly or taking only fluids for a period beforehand and a laxative preparation the day before. Preparations vary between departments, so follow the written instructions sent with your own appointment.

How long does the test take? The examination itself is a single appointment in the X-ray department, during which a series of images is taken as the barium fills and coats the bowel and you change position. The video on this page shows the examination in just over four minutes of footage; your appointment will be longer than the filming, to allow for preparation, positioning and checking the images.

Why might I be offered a barium enema instead of a colonoscopy? The two tests look at the bowel differently. A barium enema maps the outline and overall shape of the colon on X-ray, while colonoscopy views the lining directly and can take samples. Your clinician will explain which examination — or which combination — fits the question being investigated in your case.

MedicalVideos.com has published trusted medical videos since 2007. The site was founded by Dr. Mohamed Ibrahim, MD, PhD — physician-scientist.

Educational only — this article is general information about barium enema examinations, not medical advice and not a diagnosis. Whether this test is right for you, and how to prepare for it, are matters for your own clinician and radiology department, who know your history.