Thymic stromal lymphopoietin (TSLP) is elevated in asthma and triggers dendritic cell-mediated activation of TH2 inflammatory responses. Viral stimuli, a major cause of asthma exacerbations, have been shown to induce overexpression of TSLP in asthmatic epithelium. Azithromycin has various anti-microbial and antiinflammatory effects. However, the effect of azithromycin on the production of TSLP has not been studied. Here we explored the effects of azithromycin on viral surrogate (dsRNA)-induced TSLP in normal human bronchial epithelial (NHBE) cells. NHBE were stimulated with poly (I:C) in the presence azithromycin. The effects of azithromycin on dsRNA-induced inflammatory responses in NHBE cells were analyzed. We demonstrated that azithromycin inhibited the production and mRNA expression of TSLP in NHBE cells. Azithromycin also inhibited the nuclear factor-KB luciferase activity induced by poly (I:C), and it prevented dsRNA-induced loss of the NF-kappaB repressor protein IkappaBalpha. These results suggest that azithromycin can be useful to treat asthma exacerbations due to the inhibition of TSLP.