Gastro-oesophageal reflux disease (GORD) is defined as a condition which develops when the reflux of stomach contents causes troublesome symptoms and/or complications. Many patients with GORD complications such as oesophagitis and up to a third of patients with Barrett's oesophagus have no reflux or heartburn symptoms. Conversely, patients can be symptomatic even when normal reflux levels are found and there is an absence of mucosal damage.