New approaches to the grading of reflux oesophagitis and the definition of reflux disease have been proposed which should improve the precision of descriptions of this common problem. Endoscopy and 24-hour pH monitoring studies, though of great value, have significant limitations for assessment of reflux disease. Only about one third of reflux disease patients have oesophageal mucosal erosion or ulceration. Analysis of symptoms is probably the most useful method for diagnosis. Further research is needed into the best strategies for maximising the potential of symptom analysis. In the pathogenesis of reflux disease, Helicobacter pylori infection is not a major factor but the interaction of H. pylori gastritis and eradication therapy are important areas of great current interest. Troublesome reflux disease arises primarily from abnormally frequent gastro-oesophageal reflux, though heightened oesophageal mucosal sensitivity and defective oesophageal clearance play a role in some patients. Transient lower oesophageal sphincter relaxation appears to be the most important mechanism of reflux. This distinctive, swallow-independent type of lower oesophageal sphincter relaxation has a complex triggering system, apparently located in the brain stem. Medical and surgical treatments of reflux disease are now well characterised and have improved very substantially over recent years. Drugs that inhibit the occurrence of transient lower oesophageal sphincter relaxation are an intriguing possible future therapy.