The role of corticosteroids in the management of severely ill patients with influenza A(H1N1)viral infection is unclear and controversial.Two critically ill cases with influenza A(H1N1)infections complicated with organizing pneumonia(OP)in 2011 successfully treated with low dose corticosteroids were reported here.After initial clinical improvement,the condition of both patients aggravated 20-23 days after the onset of illness.Chest X-ray and computed tomographies(CT)showed an increment of lung infiltrates.Cultures of The role of corticosteroids in the management of severely ill patients with influenza A (H1N1) viral infection is unclear and controversial. Two critically ill cases with influenza A (H1N1) infections complicated with organizing pneumonia (OP) in 2011 successfully treated with low dose corticosteroids were reported here. After the initial clinical improvement, the condition of both patients aggravated 20-23 days after the onset of illness. Chest X-ray and computed tomographies (CT) showed an increment of lung infiltrates.