A barium meal is an x-ray imaging test used to examine the stomach and duodenum for abnormalities like ulcers or tumors. It involves drinking barium sulfate suspension and taking x-ray images. It is indicated when investigating unexplained weight loss, dyspepsia, or gastrointestinal bleeding. Contraindications include complete bowel obstruction or suspected perforation. There are three types - single, double, and bi-phasic contrast. The test is extremely safe and noninvasive, and allows accurate evaluation of the upper GI tract. It can detect conditions like erosive gastritis, hiatal hernia, or pyloric stenosis.