barium meal Some compounds of barium are poisonous, but barium sulphate is a harmless, white, insoluble substance that can be made into a tasteless suspension which is ‘radio-opaque’. This can be swallowed as a ‘barium meal’ to aid diagnosis of disorders of the upper gastrointestinal tract (a ‘barium enema’ is a similar suspension that is introduced into the large intestine through the rectum, for the investigation of disorders of the lower tract). The opaqueness of the material allows it to be visualized easily by X-ray as it passes down the oesophagus and through the stomach and upper intestine. The material will fill cavities caused by ulcers, and outline abnormal growths in the tract, thus giving visual information about dysfunction or disease of component parts, such as duodenal ulcer or stomach cancer.

E. M. (Tilli) Tansey

barium meal n. a technique for examining the oesophagus, stomach, and duodenum. The patient swallows barium sulphate to coat the lining of the organs, and a series of X-rays is taken. Granules that produce gas to distend the stomach may be given to produce a double-contrast effect.