[Definition and classification of GERD].

Gastro-esophageal reflux disease(GERD) is a condition which develops when the reflux of stomach contents causes troublesome symptoms and/or complications. Traditionally, it was defined as a condition in which either or both of reflux esophagitis and reflux symptoms can be identified. The Montreal definition expanded the category of GERD to complications of esophagitis and extra-esophageal symptoms with or without established evidence on the correlation with GERD. Symptomatic patients those who lacks the evidence of mucosal breaks are called as NERD. Functional heartburn, defined in Rome III, is similar in symptoms but different in the responsiveness to PPIs. Increasing knowledge will clarify what the gastroesophageal reflux really causes health problems.