This is an overview of the pathophysiological abnormalities of gastroduodenal (GD) ulcers [duodenal ulcer (DU), gastric ulcer (GU) and Dragstedt ulcers (combined DU and GD)], as well as the effects of the different treatments (surgical, medicinal and physiological) described since the introduction of stomach resections. The intention is to demonstrate whether the peptic ulcer diseases are a homogeneous entity with a characteristic pathophysiology or whether they represent the final expression of many heterogeneous causes including impairment of upper gastrointestinal motility. The review also asks whether DU and GU have a common or different pathogenesis and whether ulcers in the stomach might be predominantly due to impaired mucosal resistance and the DU to gastric hypersecretion. The symptoms of both diseases are also compared with the findings in the normal controls.