Functional (nonulcer) dyspepsia is meal-related epigastric discomfort also known as indigestion without an ulcer by x-ray or endoscopy. In other words, it is dyspepsia after a history, physical and initial investigations have ruled out organic disease. This discomfort may be associated with nausea, vomiting, belching, bloating and flatulence. Usually, the causes of dyspepsia include peptic ulcer disease, gastroesophageal reflux disease and drug-induced symptoms from aspirin or nonsteroidal antiinflammatory drugs. However, functional dyspepsia accounts for 50% of all dyspepsias.
While the etiology is unclear, it is thought to be multifactorial, having to do with motility, sensory disturbances and psychosocial issues.