This document provides information about various radiological studies of the gastrointestinal tract including barium swallow, barium meal, barium follow through, and barium enema. It describes the anatomy of the esophagus and conditions that can be examined using barium swallow such as achalasia, Barrett's esophagus, and esophageal cancer. Techniques, indications, contraindications and findings for each study are summarized. Common abnormalities that can be identified on these studies including ulcers, polyps, tumors and inflammatory conditions are also outlined.