Certain oriental medication have been shown to be effective in decreasing pulmonary vascular resistance and increasing cardiac output in primary pulmonary artery pressure secondary to pulmonary edema. So oleic acid was administered in 14 dogs in order to induce acute lung injury. And we studied the hemodynamics and blood gas changes of Pyengpaetang(50mg, 100mg) with continuous postive pressure was ventilation in pulmonary edema. The pulmonary edema group, arterial oxygenation was improved after 5 and $10cmH_2O$ PEEP(positive end expiratory pressure), but cardiovascular system was depressed. Blood pressure and cardiac output were decreased, and CVP, MP AP, PCWP were increased. In Pyengpaetang(50mg) group, mean aortic pressure was decreased and PCWP(pulmonary capillary wedge pressure) was decreased remarkably, while there was a significant increase in cardiac output. And there was improvement in $PaO_2$ and $PaCO_2$ without hemodynamic changes after applying 5cm $H_2O$ PEEP, but arterial blood gases$(PaO_2,;PaCO_2)$ were improved, while cardiovascular effects were depressed after cm $H_2O$ PEEP. In Pyengpaetang(100mg) treated group, there was no significant hemodynamic change. But mean pulmonary arterial pressure was significantly increased, and cardiac output was decreased significantly after applying the more degree of PEEP. And blood gases were not changed significantly after applying the more degree of PEEP. The above results suggest that the effects of Pyengpaetang(50mg) group is superior to those of Pyengpaetang(100mg) group on the effects of hemodynamics and gas exchanges in acute lung injury in dogs. So we can conclude that lower degree PEEP 5cm $H_2O$ is more beneficial in Pyengpaetang(50mg) treated group.