Abstract： Objective To investigate the therapeutic effects and safety of extracorporeal membrane oxygenation (ECMO) in patients with acute respiratory distress syndrome (ARDS).Methods ECMO were initiated in 6 patients with ARDS, not responding to conventional mechanical ventilation. Oxygenation status, positive end-expiratory pressure (PEEP) level,and fraction of inspired oxygen (FiO2) were compared before and after treatment with ECMO,while the adverse effects of ECMO were recorded.Results In 6 cases,pulse blood oxygen saturation (SpO2) was elevated (0.45-0.92 up to 0.94-1.00),PEEP level (cm H2O,1 cm H2O=0.098 kPa) and FiO2 were lowered (PEEP:10.0-22.0 down to4.0-15.0; FiO2:1.00 down to 0.30-0.60) after treatment with ECMO.Of 6 cases,2 patients with severe influenza A/H1N1 pneumonia finally died of shock; 1 patient with severe influenza A/H1N1 pneumonia and 1 patient with Klebsiella pneumoniae pneumonia were withdrawn from ECMO treatment because of deterioration of the disease.One patient suffering from Cytomegalovirus pneumonia and another with Acinetobacter baumanii pneumonia were successfully discharged from hospital with recovery.The main complications were bleeding and hemolysis.Conclusions ECMO could improve gas exchange,oxygenation and partially replace pulmonary function.Patients with ARDS should be treated with ECMO early if artificial ventilation treatment was unresponsive.