Adult respiratory distress syndrome is a complex disease resulting in lung dysfunction secondary to a primary nonpulmonary catastrophic event. Many mediators are involved in the destructive chain of events occurring at the cellular level. Investigation of ARDS continues, with efforts directed toward blocking those mediators and thereby alleviating the lung damage and hypoxia once this cascade has been initiated. Even with these advances, however, current optimal therapy is directed toward reversing the primary inciting event and providing the supportive care required to survive the acute episode.