A barium enema is a procedure used to examine the lining of the colon and rectum. The procedure is also called a lower gastrointestinal series.
Barium refers to barium sulfate, a chalky chemical that appears white on X-ray film. Enema refers to any fluid pumped into the rectum through the anus. After the barium sulfate liquid makes its way to your intestines, a series of X-ray pictures are taken. In these X-rays, the white barium fluid allows some abnormalities in the lining of the intestines to appear dark. Air may be pumped into the intestine during this procedure to help sharpen the outline of the intestinal wall.
This test takes about 45 minutes. It can be done as an outpatient procedure, meaning you don't have to stay overnight in a hospital. Although the X-rays themselves are painless, the enema may cause some slight discomfort. You may feel full or gassy.