GERD is the acronym for gastro-esophageal reflux disease. GERD is due to a weakened lower esophageal sphincter (LES). This sphincter is a “door” between the esophagus and the stomach that normally remains closed and only opens to allow food to pass into the stomach, allows a burp to escape or allows vomitting. In patients with GERD, the LES remains relaxed, allowing stomach acid to bathe the lower esophagus. This acid burns the lining of your esophagus presenting as what is often called “heartburn.” It feels like a burning sensation in the middle of the chest. Chronic irritation can permanently damage the delicate inner lining of the esophagus.