A hiatal hernia is a condition in which the upper part of the stomach bulges through an opening in the diaphragm. The diaphragm is the muscle wall that separates the stomach from the chest. The diaphragm helps keep acid from coming up into the esophagus. When you have a hiatal hernia, it's easier for the acid to come up. The leaking of acid from the stomach into the esophagus is called gastroesophageal reflux (GERD). GERD may cause symptoms such as Heartburn Problems swallowing A dry cough Bad breath Hiatal hernias are common, especially in people over age 50. If you have symptoms, eating small meals, avoiding certain foods, not smoking or drinking alcohol, and losing weight may help. Your doctor may recommend antacids or other medicines. If these don't help, you may need surgery.