A series of radiographic images taken of the stomach and duodenum after the contrast agent barium has been swallowed is an upper GI series, where GI<span> stands for "</span>gastrointestinal<span>," which means "stomach and intestines". </span>This x-ray examination of the upper gastrointestinal<span> (</span>GI<span>) tract,</span>can diagnose problems in your upper GI tract, how to prepare for the procedure, and what to expect afterwards.