 The acute respiratory distress syndrome ARDS is a syndrome of severe acute lung inflammation and hypoxemic respiratory failure with an incidence of 180,000 cases annually in the U.S.Despite decades of research and recent advances in lung protective ventilator strategies, morbidity and mortality remain unacceptably high. Furthermore, no specific effective pharmacologic therapies currently exist. The lack of specific effective therapies for sepsis-related ARDS indicates a need for new treatments that target novel pathways. Carbon monoxide CO represents a novel therapeutic modality in ARDS based on data obtained in experimental models of ARDS and sepsis over the past decade. 