Barium meal is a medical diagnostic procedure in which the patient swallows barium sulfate, a metallic compound that appears opaque on x-rays, to highlight the gastrointestinal tract. There are a few synonyms used for this procedure including barium swallow, upper GI series, and esophagram. Barium swallow is a more general term encompassing all procedures involving swallowing barium sulfate - although it usually refers specifically to the esophagus, whereas barium meal is more commonly used to refer to the whole procedure from mouth to rectum. Upper GI series is a more technical term, and esophagram restricts the procedure to just the esophagus, but all are used interchangeably.