The organs of the digestive system don't show up on x-ray unless they are 'outlined' by barium meal. This is a medical test used to examine the condition of the digestive tract using a heavy, white, radio-opaque powder called barium sulfate. This powder is usually flavoured and mixed with a liquid which is then swallowed by the patient. The mixture passes quickly into the digestive tract and its progress is followed by taking x-rays over different periods of time, depending on which part of the digestive tract the doctor wants to observe.
Barium meal is a test that allows your doctor to view the upper part of your bowel, using a white fluid called barium to outline the shape of the throat and stomach, and a fizzy drink to open up the walls of the stomach.
A barium swallow involves x-ray examination of the oesophagus, and is used to help diagnose swallowing or reflux problems.
A barium meal-barium swallow test -is ordered for people who are having trouble swallowing, or having unexplained pain or vomiting. It provides useful information about the condition of your gullet and stomach, and can make or confirm a diagnosis.
A similar examination of the large intestine, or colon, is called a Barium enema, or Lower GI. Of course, in this instance, the barium is not swallowed, but is given rectally as an enema - thus the more common name, Barium Enema. This examination takes less than an hour and requires fasting as well as an unpleasant laxative and dietary preparation the day or two before. Prep instructions vary and will be provided and be sure to follow them exactly so the test need not be repeated.