Symptomatic gastroesophageal reflux is a common medical problem. But only few data exist on the epidemiology of reflux disease (without inflammation) and reflux esophagitis. The literature is critically reviewed and ecological causes of gastroesophageal reflux are discussed. The prevalence of reflux esophagitis in Western countries is estimated to be 2% and that of reflux disease 5%. Sparse reports exist on the natural history of both diseases. They appear to have little if any effect on life expectancy. The main complications of reflux esophagitis are Barrett's esophagus, peptic stricture, ulceration and bleeding.