 The clinical syndrome of ARDS is defined as refractory hypoxemia with bilateral infiltrates on chest radiograph in the absence of left atrial hypertension. Pathophysiologically, ARDS is characterized by diffuse alveolar damage, increased pulmonary alveolar-capillary permeability, and the subsequent accumulation of extravascular lung water. In animal models of chronic alcohol abuse, we showed that chronic ethanol ingestion causes chronic oxidative stress, depletes lung glutathione, impairs alveolar-capillary barrier function, and exaggerates endotoxin-mediated acute lung injury. Ethanol-mediated disruption of the alveolar-capillary barrier, and the associated susceptibility to acute edematous injury, is modified by glutathione GSH replacement therapy in animal models. 