Gastroesophageal reflux disease (GERD) is a more serious form of gastroesophageal reflux more commonly known as heartburn or acid reflux. Acid reflux occurs when the lower esophageal sphincter opens spontaneously, or does not close properly, and stomach contents rise up into the esophagus.
When acid reflux occurs, food or fluid can be tasted in the back of the mouth. When refluxed stomach acid touches the lining of the esophagus it may cause a burning sensation in the chest or throat called heartburn or acid indigestion. Occasional acid reflux is common and does not necessarily mean one has GERD. Persistent reflux that occurs more than twice a week is considered GERD, and it can eventually lead to more serious health problems.