What is GERD (acid reflux)?

Gastroesophageal reflux disease, commonly referred to as GERD, or acid reflux, is a condition in which the liquid content of the stomach regurgitates (backs up, or refluxes) into the esophagus. The liquid can inflame and damage the lining of the esophagus although this occurs in a minority of patients. The regurgitated liquid usually contains acid and pepsin that are produced by the stomach. (Pepsin is an enzyme that begins the digestion of proteins in the stomach.) The refluxed liquid also may contain bile that has backed-up into the stomach from the duodenum. (The duodenum is the first part of the small intestine that attaches to the stomach.) Acid is believed to be the most injurious component of the refluxed liquid. Pepsin and bile also may injure the esophagus, but their role in the production of esophageal inflammation and damage (esophagitis) is not as clear as the role of acid.