A barium swallow is a type of test used to look inside the esophagus, or food pipe. A doctor might recommend this test if they need to look at the outline of any part of a person’s digestive system.

Fluoroscopy shows that on swallowing, the barium column moves down the esophagus. Such barium movement occurs largely due to passive forces in the esophagus and is very marked in the upright position.