The hemodynamic and oxygen transport effects of prostaglandin E1 (PGE1, Prostin -VR), in increasing doses from 1 to 30 ng/kg X min were evaluated in 5 severely ill surgical patients with adult respiratory distress syndrome (ARDS). This agent produced marked reductions in pulmonary arterial and venous pressures, and increases in cardiac output and oxygen transport. Improvement in PaO2 occurred several hours after these effects. The data indicate that this agent may be a useful adjunctive therapy for ARDS.