Gastroesophageal reflux disease (GERD) is a more serious form of gastroesophageal reflux (GER), which is common. GER occurs when the lower esophageal sphincter (LES) opens spontaneously, for varying periods of time, or does not close properly and stomach contents rise up into the esophagus. GER is also called acid reflux or acid regurgitation, because digestive juices—called acids—rise up with the food. The esophagus is the tube that carries food from the mouth to the stomach. The LES is a ring of muscle at the bottom of the esophagus that acts like a valve between the esophagus and stomach.
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 GER 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. People of all ages can have GERD.