A barium enema is a test used to help see the outline of the large bowel (colon).
Note: the information below is a general guide only. The arrangements, and the way tests are performed, may vary between different hospitals. Always follow the instructions given by your doctor or local hospital.
What is a barium enema?
A barium enema is used to look for problems in the large bowel (colon). These problems may include:
- Small fleshy lumps (polyps).
- Inflammation (colitis).
- Narrowing of the colon.
- Small pouches (diverticula) which stick out from the wall of the gut (intestines).
The gut does not show up very well on ordinary X-ray pictures. However, if a liquid that contains barium is placed in the gut, the outline of the gut shows up clearly on X-ray pictures. This is because X-rays do not pass through barium. A thick white liquid that contains barium is used as an enema to place in the colon.
Barium liquid can also be taken as a drink and is used to obtain clear X-ray pictures of the upper gut - the gullet (oesophagus), stomach and small intestine. See separate leaflet called Barium Swallow/Meal/Follow Through for more details.
What is the preparation before a barium enema?
Any poo (faeces) needs to be cleared from your large bowel (colon) before the test. So, you should be given some strong laxatives, and instructions on how to use them, from your doctor or the hospital department which does the test.
You should also be advised on the kind of food to eat for a day or so before the test.
You will usually be advised to carry on with your normal medication, except for iron tablets.
How is a barium enema done?
You will be asked to wear a gown and to lie on a couch on your side or front. A small tube is then put into your back passage (anus) and gently pushed up a few centimetres. Barium liquid is then passed through the tube into your large bowel (colon).
The aim is to get the barium liquid to spread all along the colon as far as the point where the small intestine joins the colon (the caecum). To help with this, the person doing the test may:
- Ask you to move into different positions on to your back, sides, etc, to help with the flow of the barium liquid.
- Give you an injection of a drug that makes the muscles in the wall of the colon relax.
- Pass some air down the enema tube into the colon. (This may feel a little uncomfortable - like 'trapped wind'.) The air expands the colon and also pushes the barium to coat the lining of the colon. This makes the X-ray pictures much clearer. It is the shape and contours of the lining of the colon which need to be seen most clearly on the pictures.
When the barium has spread throughout the colon, several X-ray pictures are taken with you in different positions. The aim is to have pictures of all parts of the colon. (Low-dose X-rays are used so the total amount of radiation for the whole test is quite small and thought to be safe.)
The tube is then removed and you can go to the toilet. The test takes about 15-20 minutes.
Are there any side-effects or risks from a barium enema?
- Some people feel a little sickly or have stomach cramps for a few hours afterwards.
- The barium may make you constipated. So, to help prevent constipation:
- Have lots to drink for a day or so to flush the barium out of your gut (intestines).
- Eat plenty of fruit for a day or so.
- See your doctor if you haven't passed any poo (faeces) after three or four days.
- If you had an injection to relax the muscles in your large bowel (colon), it may cause some blurring of your vision for an hour or so. If this happens it is best not to drive until this passes.
- The barium does not get absorbed into the body. So, it is rare for a barium test to cause any other complications or side-effects. Rare complications are:
- A small hole (perforation) of the colon being made. This is generally only a risk if you have a badly inflamed colon.
- A reaction to the injection of muscle relaxant mentioned above.
- During the procedure several X-ray pictures will be taken. This will involve you being exposed to a small amount of radiation. This amount is about the same as you would get in everyday life over three years. It is thought to be safe.
After you have had a barium enema
- You should be able to go home as soon as the test is finished. However, you may have some stomach cramps due to some 'trapped air'. So, you may want to stay near a toilet for an hour or so.
- You can eat normally straight afterwards.
- The barium will make your poo (faeces) white or pale until it has all passed out from your large bowel (colon). This may take a day or so.
Some other points about a barium enema
- Tell your doctor if you have insulin-dependent diabetes, so that you can arrange for the best time for you to stop eating and for the test to be done.
- Pregnant women, if possible, should not have an any X-ray test as there is a small risk that X-rays may cause an abnormality to the unborn child. This is why women are asked before having an X-ray whether they are, or might be, pregnant.
- A barium enema is done less commonly these days, as the more common test to look inside the large bowel (colon) is with a flexible telescope (colonoscopy). However, there is still a place for a barium enema to help to diagnose and assess various conditions of the gut (intestines).
Dr Tim Kenny
Dr Laurence Knott
Dr Helen Huins