An anatomic and radio-anatomic study of 15 specimens enabled us to reconsider the arterial vascularization of the duodenal bulb and to propose a new classification based on anatomoclinical criteria. The two arterial pedicles (infra- and supradudodenal) reach the bulb on its posterior aspect; each pedicle is made up of two sorts of blood currents (right and left); the posterior aspect of the bulb seems to be the most vascularized one, explaining, apart from bleeding from gastroduodenal a. erosion, the hemorrhagic character of ulcers of the posterior aspect of the bulb. The predominance of the left-hand currents explains the possible ischemia of the duodenal bulb and/or rupture of the duodenal stump after their interruption.