Hiatal hernia is a protrusion of a portion of the stomach through the muscular ring at the junction of the esophagus and stomach. In most cases it produces no symptoms, but, depending on diet and other factors, the herniated portion of the stomach can become irritated or cause acid to reflux into the lower portion of the esophagus. The result is upper gastrointestinal distress - heartburn, belching, distension, difficulty in swallowing, regurgitation.