The adult respiratory distress syndrome (ARDS) is an extreme form of noncardiogenic pulmonary edema associated with alveolar-capillary damage. Clinical features include acute respiratory distress, dyspnea and tachypnea, severe hypoxemia refractory to oxygen therapy, and diffuse bilateral pulmonary infiltrates. Any number of serious disorders can cause ARDS, but the processes leading to the alveolar permeability defect are not understood. Therefore, therapy remains nonspecific and supportive. Treatment includes positive end-expiratory pressure, careful fluid management, steroid therapy, and adequate nutrition. Unfortunately, even with the most sophisticated intensive care, the mortality of ARDS is still greater than 50%.