Abstract: Objective: To study the effects of perfluorocarbon on the function of rabbit alveolar macrophages and the probable mechanism of the decrease in pulmonary inflammation seen in animals treated with partial liquid ventilation during acute lung injury. Methods: Rabbit alveolar macrophages were exposed to perfluorodecalin. The production of hydrogen peroxide, tumor necrosis factor-α and nitric oxide was measured after potent stimuli. Results: Perfluorodecalin exposed alveolar macrophages produced significantly less hydrogen peroxide, tumor necrosis factor-α and nitric oxide. Conclusion: Exposure of alveolar macrophages to perfluorodecalin in vitro decreases the responsiveness of alveolar macrophages to potent stimuli. The decrease in pulmonary inflammation seen in animals treated with partial liquid ventilation during acute lung injury might be associated with the less production of hydrogen peroxide, tumor necrosis factor-α and nitric oxide by alveolar macrophages.