Pulmonary edema is differentiated into two categories--cardiogenic and noncardiogenic. Noncardiogenic pulmonary edema is due to changes in permeability of the pulmonary capillary membrane as a result of either a direct or an indirect pathologic process. It is a spectrum of illness ranging from the less severe form of ALI to the severe ARDS. The mainstay of treatment is mechanical ventilation with maximization of ventilation and oxygenation through the judicious use of PEEP. Newer ventilation techniques, such as high-frequency oscillatory ventilation and partial fluid ventilation, are promising but are in the early stages of clinical testing. Mortality rates remain high despite increasing intensive care unit care.