Functional dyspepsia is characterised by troublesome early satiety, fullness, or epigastric pain or burning. It can easily be overlooked as the symptoms overlap with gastro-oesophageal reflux disease and irritable bowel syndrome. Diagnosis is clinical, however it requires exclusion of structural gastrointestinal disease. The presence of red flags, such as weight loss or anaemia, should prompt investigation including gastroscopy. The pathophysiology of functional dyspepsia is not completely understood. It is thought to be associated with upper gastrointestinal inflammation and motility disturbances, which may be triggered by an infectious or allergenic agent, or a change in the intestinal microbiome. Slow gastric emptying occurs in 20% of cases. While functional dyspepsia is distressing and affects quality of life, it has no long-term impacts on mortality. There are many treatment options available, with varying levels of evidence of efficacy. These include reassurance, dietary modification, acid suppression, prokinetic drugs including fundic relaxors, tricyclic antidepressants, rifaximin and psychological therapy.