Originally published by Harvard Health.
What is the test?
A barium swallow, or upper GI series, is an x-ray test used to examine the upper digestive tract (the esophagus, stomach, and small intestine). Because these organs are normally not visible on x-rays, you need to swallow barium, a liquid that does show up on x-rays. The barium temporarily coats the lining of the esophagus, stomach, and intestine, making the outline of these organs visible on the x-ray pictures. This test is useful for diagnosing cancers, ulcers, problems that cause narrowing of the esophagus, some causes of inflammation in the intestine, and some swallowing problems.
How do I prepare for the test?
Tell your doctor and the x-ray technicians if there is any chance you could be pregnant. If you have diabetes and take insulin, discuss this with your doctor before the test.
Stop eating and drinking the night before your test. This is important because food in your stomach or intestine could prevent the doctors from seeing a clear outline of these structures on the x-rays. Usually it isn’t a problem for you to take your regular pills, but you should check with your doctor.
What happens when the test is performed?
You wear a hospital gown for the test. At the start of the test, you drink barium, a liquid that looks like a milk shake but does not taste nearly as good (most patients say it tastes like chalk). You might also be asked to swallow some tablets that “fizz,” causing air-bubbles to be released in your stomach. This might make you feel like burping, but try not to. You will get better pictures if you can keep yourself from burping.
The x-ray technician may ask you to stand or lie in different positions over the next few minutes, to help spread around the liquid you have swallowed. Most often, the x-ray pictures are taken while you lie on your back on a table. The x-ray machine or the table is moved a few times so it can take pictures of all of the internal structures. You are asked to hold your breath for each picture so that your breathing movement does not blur the image.
What risks are there from the test?
There are no significant risks. You are exposed to a small amount of radiation during the test, but the amount of radiation is too small to be likely to cause any health problems.
Must I do anything special after the test is over?
After the test, you can eat normally and do your normal activities. You should drink more water than usual to help clear out the barium and to prevent constipation, which might be a side effect of the test. Your stool may appear light in color for a couple of days.
How long is it before the result of the test is known?
It takes the x-ray department 30 minutes to an hour to develop the pictures from your barium swallow, and it will take additional time for a doctor to examine the x-rays and to decide how they look. Typically you can get the results within a day or two.