The Facts
GERD stands for gastroesophageal reflux disease, which is the backflow of stomach contents (including stomach acid) upward into the esophagus, which is the swallowing tube that extends from the mouth to the stomach. The lining of the stomach protects the stomach from the effects of its own acids. Because the esophagus lacks a similar protective lining, stomach acid that flows backward (refluxes) into it causes heartburn (also called dyspepsia).
Many people experience heartburn occasionally; however, people who get severe heartburn several times a week are considered to have GERD.