Gastroesophageal reflux is a very common pathology which is genrally caused by acid reflux from the stomach to the oesophagus. (Not the rarer bilious reflux which may happen after a stomach operation).

GERD is due to the incompetence of a physiological one-way valve close to the base of the oesophagus (inferior sphincter of the oesophagus) and is usually made worse by anatomic anomalies of the oeso-gastro junction. (cardiotuberositary malposition, hiatus hernia). Without treatment, the repeated burning of the oesophagus by acid digestive juices can cause oesophagitis which in turn can induce severe complications (ulcerations, hemorragy, narrowing of the oesophagus called peptic stricture, the replacement of the normal oesophagus mucosa by a special gastric mucosa, called endobrachyoesophagus, which can potentitally turn into cancer after several years and requires a indefinite surveillance and biopsies.