Selective intraarterial infusion of vasopressin was performed in 32 patients for 35 episodes of gastrointestinal bleeding. Active bleeding was from esophageal varices in 11 cases and from an arterial site in 22 (stomach 11, duodenum 1, jejunum 2, colon 7, liver 1), including a jejunal diverticulum and a colonic ulcer in Behcet's disease. Two patients, not actively bleeding, were infused for portal decompression before an elective mesocaval shunt. Active bleeding was controlled in 64% of patients with variceal hemorrhage and in 59% of those with arterial sources. Infusion periods ranged from 15 minutes to 70 hours. There were no significant complications directly attributable to this therapy. © 1976 Springer-Verlag.