A barium swallow involves drinking barium liquid and undergoing x-ray imaging to examine the esophagus, stomach, and small intestine. Patients are asked to avoid eating or drinking before the test and to hold their breath during imaging. The barium coats the digestive tract and allows visualization of any abnormalities. Results are usually available within a day or two as doctors examine the x-rays for signs of issues like ulcers, cancers, or narrowing. The test carries minimal risks from radiation exposure.