Listen to the Cancer.Net Podcast: Barium Enema–What to Expect , adapted from this content
A barium enema is an x-ray of the colon and rectum. The colon and rectum make up the large intestine, which helps the body process waste. A barium enema helps doctors uncover health conditions in the colon and rectum, such as inflammation, polyps, and cancer. Barium is a contrast medium. A contrast medium is a substance used to make clearer images of the inside of the body.
Who does my barium enema?
A radiology technician or a radiologist performs a barium enema in an x-ray room in either a hospital or a doctor's office. The radiologist then interprets the results and diagnoses or confirms any abnormalities.
Getting ready for a barium enema
When you schedule the barium enema, you will get detailed instructions on how to prepare. Because your colon must be completely empty, you can eat only soft foods or clear liquids for 1 to 3 days beforehand. This includes fat-free bouillon or broth, black coffee, and strained fruit juice.
You will also need to take a laxative or give yourself an enema the day or night before your appointment. This step removes any remaining waste from your colon. If your doctor prescribes a laxative, it will be either a pill or a powder that you mix with water before drinking. The laxative will make you use the bathroom frequently. Make sure you have easy access to a bathroom during this time. You will not be allowed to eat or drink anything after midnight on the day of your procedure.
Before the procedure, talk with your health care team about:
All of the medications you are taking and any drug allergies you have. Also, tell your doctor if you are allergic to barium.
Whether you should take your usual medications on the day of the procedure.
Any medical conditions you have. A women should tell her doctor if there is any chance that she is pregnant. X-rays are harmful to a developing baby.
Any concerns you may have about the test.
Before your appointment, find out from your insurance provider what costs will be covered. And, ask if there are any additional costs you must pay yourself. Once you arrive at the doctor's office or hospital, you will be asked to sign a consent form. This form states that you understand the benefits and risks of the procedure and that you agree to have it.
During the procedure
A barium enema usually takes 20 to 30 minutes to complete. You will be asked to remove all clothing, jewelry, and any other metal objects that could interfere with the x-ray. You will be given a hospital gown to wear.
When you are ready, the doctor or technician will direct you to lie on your side on an exam table in a private room. He or she will drape a sheet over your body. The exam table is attached to an x-ray machine and a video monitor.
The x-ray technologist will begin by taking several x-rays to make sure your colon is empty. The doctor or technician will insert a well-lubricated enema tip attached to a tube into your anus. The radiologist will then insert barium into your colon through the tube.
The doctor or technician may ask you to move into different positions during the test. This is so the barium can flow through the entire colon. Once the radiologist determines there is enough barium in the colon, he or she may deliver a small amount of air into the colon through the same tube. This step is called a double contrast barium enema. It inflates the bowel and produces a better view of the intestinal wall. Several x-rays will be taken during this time. When an x-ray is taken, the barium shows up bright white, clearly outlining the colon and rectum.
You may feel mild stomach pressure and cramping when the barium flows through the colon. Taking slow, deep breaths can make you more comfortable. You may also feel discomfort from lying still for a long time. Once the barium is inserted into the colon, you may also feel the urge to have a bowel movement. It is important for you to try to hold in the barium until the test is complete.
After the procedure
Once the radiologist has taken enough images of the colon, he or she will remove the enema tip. You will be helped down from the table so you can go to the restroom to push out the barium. You will then return to the exam room for another x-ray to make sure you have emptied your bowel enough.
You may notice gray or white stool for several days after a barium enema. That is the remaining barium leaving your body. Your health care team may recommend taking a laxative when you return home to avoid constipation from the barium. This will also help remove any remaining barium.
Drink plenty of fluids for the next several days to help prevent constipation. Call your doctor’s office immediately if you have:
Severe stomach pain
Bloody bowel movements
You can go back to your usual activities immediately after the barium enema. But it is a good idea to have someone else drive you home from the test. If your doctor finds any areas of concern during your barium enema, additional tests may be needed to examine them more closely.
Questions to ask your health care team
Before your barium enema, consider asking the following questions:
Why are you recommending this procedure?
Who will perform the barium enema? Who else will be in the room?
What will happen during the test?
How long will it take?
Will it be painful?
Are there risks associated with having a barium enema?
Will I need to avoid any activities afterward?
How accurate is a barium enema at finding cancer?
When will I learn the results? How will they be communicated to me?
Who will explain the results to me?
What other tests will I need if the barium enema finds evidence of cancer?
RadiologyInfo.org: X-ray (Radiography) - Lower GI Tract 
MedlinePlus: Barium Enema