Acid reflux disease, also know as GERD or gasroesophageal reflux disease, is caused by an esophageal sphincter that does not function properly. This sphincter is a muscular ring at the bottom of the esophagus that prevents stomach contents from backing up into the throat and mouth. If that sphincter is not working right, the acids from the stomach can come back into the esophagus causing painful heartburn, burning in the throat, and an acidic taste in the mouth.
