What Is Barium Sulfate?

Barium Shows Up White On X-Rays, Helping Your Doc See Your Insides

Colon Polyp
A polyp is highlighted on this film of a colon that was taken during a test that used colored barium sulfate solution as a contrast medium.. Image © CNRI / Science Photo Library / Getty Images

Even though it is commonly called "barium," the solution that is used for medical tests is actually not made of barium alone. Pure barium is an element that is found in combination with other elements because it reacts with air, and therefore must be extracted and isolated, usually from the mineral barite. The word barium is derived from the Greek word for heavy, "barys." Beyond its medical applications, barium has various uses in the manufacturing and drilling industries and is also the additive in fireworks that creates green colors.

Barium Sulfate

The barium solution used in radiological tests is often called by other names including "contrast medium," "barium enema," "barium swallow," "barium meal," or "barium salts." This substance is actually barium sulfate (BaSO4), a powder which has some unique properties that make it useful in imaging tests. For starters, barium sulfate is metallic, chalky, and does not dissolve in water, which is the property which causes it to pass through the body without being absorbed. Secondly, barium sulfate is heavy and scatters x-rays, which means that it can provide a contrast on the x-ray film and help a radiologist to see internal structures. The barium will appear white on a x-ray, which can make it easier to see organs such as the small intestinelarge intestine, the stomach, and the rectum.

Barium sulfate that is drunk is typically stirred into some water and given a flavoring in order to make it easier for patients to drink.

Sometimes a carbonated drink is also given along with the barium contrast, or the barium contrast will contain carbonation. Air will appear black on an x-ray film, offering more contrast against the white that will be a result of the barium coating the inside of the digestive tract. This is called a double-contrast study.

Barium sulfate that is used for lower digestive tract tests is inserted into the rectum via the use of a tube. Air may also be added through the tube, sometimes after barium is drained out, in order for the radiologist to get a good view of the colon.

Tests That Use Barium

A barium solution is used in various radiological tests, including many that people with inflammatory bowel disease (IBD) may undergo as a part of their diagnosis and treatment. Some of these tests include:

  • Barium enema: This test, which is also called a lower gastrointestinal series, is a series of x-rays that are done after the patient receives an enema of barium sulfate.
  • Barium swallow: Also called an upper gastrointestinal series, this test is done after drinking the barium contrast solution. X-rays are taken of the upper digestive tract as the barium sulfate moves through.

Barium Toxicity

Radiological tests using barium sulfate are very safe. When it is used properly for a procedure, barium is not absorbed by the body and toxicity is not a concern.

However, it is important that the barium sulfate is cleared from the body at the end of the test. If you have had a test using barium, your physician will give you instructions for after the test. Some people may have white stools after a test using barium sulfate. Any unusual signs or symptoms after the test, such as abdominal pain, constipation, or narrow stools, should be reported to your physician.

Barium that is used for other purposes, such as fireworks, should never be ingested because it is toxic. The signs and symptoms of barium toxicity can include:


Centers for Disease Control and Prevention (CDC). "Barium toxicity after exposure to contaminated contrast solution–Goias State, Brazil, 2003." MMWR Morb Mortal Wkly Rep. 2003 Oct 31;52(43):1047-1048.

Rhyee SH, Heard K. "Acute barium toxicity from ingestion of “snake” fireworks." J Med Toxicol. 2009 Dec;5(4):209-213. 

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