In anesthetized dogs, the effects of hemorrhage alone upon the mesenteric circulation have been compared with those of hemorrhage plus l-norepinephrine. With norepinephrine, the portal venous flow is slightly less than in the case of untreated hemorrhage. In view of the significantly higher blood pressure during the norepinephrine infusions, however, the mesenteric resistance is considerably greater during infusions of this agent than in untreated hemorrhage.