[Formal cause of stomach ulcer]

Analysing gastric circulation we find that the hemodynamic effects of acid secretion and wall stress during contractions are capable of producing malperfusion of discrete areas. A computer-aided simulation of digestive cycles on a simplified gastric model shows an ischemic lesion, corresponding with the phenomenology of human gastric ulcer. A steal-phenomenon, which the effect is due to, has been produced experimentally.