Dogs [12] were subjected to hemorrhagic shock by a modified Wiggers technique. Half were treated with prostaglandin E1 [PGE1], 1 .mu.g/kg per min in 60 ml of saline solution, for 1 hr after shock, while the other half received only an equal amount of saline solution. Those dogs treated with PGE1 exhibited a significantly increased survival time and cardiac output and a significantly lowered total peripheral resistance when compared with those for untreated dogs. The various modes of action by which PGE1 exerts both its cardiovascular and other long term effects indicate a multisystem effect of the drug.