Acute lung injuries due to acute lung infections remain the major cause of mortality. Thus antibiotics with immunomodulatory and anti-inflammatory activities ,regardless of their antibacterial properties, will help to overcome acute lung infection-induced injuries. The macrolide antibiotics have been shown to possess these properties. Clarithromycin has been shown to possess anti-inflammatory properties in chronic inflammatory conditions. So we evaluated the anti-inflammatory effect of clarithromycin treatment in Klebsiella pneumoniae B5055-induced acute lung infection in mice. The clarithromycin treatment significantly (p<0.05) decreased the bacterial load in the lungs of K. pneumoniae B5055-infected mice and significantly (p<0.05) increased macrophage activity. The clarithromycin treatment also significantly ( p<0.05) decreased the neutrophil infiltration into the lungs and decreased myeloperoxidase (MPO) activity. Clarithromycin significantly (p<0.05) decreased malondialdehyde (MDA) and nitric oxide (NO) production and thus decreased acute lung injury occurring during acute lung infection.