Definition of Acid reflux Acid reflux: A common condition and an abnormal one in which acid in the stomach rises up into the esophagus. This occurs because the valve separating the contents of the stomach from the esophagus does not function properly. See also: GERD.
Acid reflux: A common condition and an abnormal one in which acid in the stomach rises up into the esophagus. This occurs because the valve separating the contents of the stomach from the esophagus does not function properly. See also: GERD.
