[1] Specifically it is used to improve visualization of the gastrointestinal tract (esophagus, stomach, intestines) on plain X-ray or computed tomography.

Consumption of the barium sulfate suspension begins 90 minutes to two hours prior to the CT/Fluoroscopic scan, as instructed in the patient education provided.

The barium sulfate is excreted through defecation, so extra fluid intake helps prevent constipation, which is a possible side effect (see Johns Hopkins Medicine Health Library for an example of a possible patient education instruction sheet).

[9] Side effects include nausea, diarrhea, a feeling of weakness, pale skin, ringing in the ears, constipation, and vomiting.

[10] Oral barium sulfate suspensions are sometimes described as having the consistency of a very thick glass of milk, or a very thin milkshake.