Chronic benignant ulcers of the stomach were considered as a disease entity not until in the 1830s, when Jean Cruveilhier and others compared disease history with pathological findings at autopsy. Ulcers of the duodenal bulb were thought unusual until in the beginning of the twentieth century, when abdominal surgery was rapidly developing and X-ray introduced as a diagnostic tool intra vitam. Duodenal ulcers and distal ventricular ulcers have a similar symptomatology and are often associated with hyperacidity. They are therefore jointly spoken as a peptic ulcer disease. Trauma and dietetic faults, hyperacidity and local circulatory disturbances were considered important etiological and pathogenetical factors in the nineteenth century. In the 1910s, instability of the vegetative (autonomic) nervous system was coined as an additional factor. However, the most important concept of the nature of peptic ulcer emerged in the 1940s, when it was appointed a psychosomatic disease. Psychoanalysis and stress research were the main sources of this concept which was predominant until recently. In the middle of the 1980s, gastric infection with a bacillus, later named Helicobacter pylori, was demonstrated to be strongly associated with peptic ulcer and is now considered as its main cause. This finding has also had an important impact on the treatment of peptic ulcer, which is now mainly pharmacological. Thus, a biogenetic view of peptic ulcer disease has superseded a psychogenetic one. The author thus proposes that the history of peptic ulcer can be divided into four periods or stages, comparable to the paradigmal shifts of Kuhn, according to the prevailing concepts of the disease. It is however concluded that peptic ulcer is no unicausal or monolithic unity but rather a syndrome with a complex etiology and pathogenesis. It is important to maintain a holistic view of the diseased individual.