- Functional heartburn = is defined as the presence of heartburn (retrosternal burning or pain) that is unrelated to oesophageal acid exposure and is not caused by gastro-oesophageal reflux.
- Functional dyspepsia = is characterised by predominant epigastric pain or burning (epigastric pain syndrome), or early satiety or discomfort after meals (postprandial distress syndrome).
- To diagnose functional heartburn or functional dyspepsia, symptoms must have been present for 6 months and investigated appropriately to exclude structural and metabolic causes