Recently, low dose and long term use of Macrolides (Mls) has been reported to be effective in treatment of chronic lower respiratory tract infections, however its mechanism is still obscure. We evaluated the effect of Mls (EM, AZM, RKM) on cytokine mRNA expressions. We preincubated the whole blood with several concentrations of Mls and removed the Mls and then stimulated human whole blood with LPS as an experimental vivo model. In order to examine cytokine mRNA expressions, we used the RT-PCR method. Cytokine mRNA expressions were suppressed significantly (p < 0.05) by pretreatment with EM, AZM; moreover, the suppression was peaked at low concentrations (0.04 approximately 0.2 microgram/ml). Although, Cytokine mRNA expressions were not suppressed by pretreatment with RKM. These results suggest that EM, AZM have suppression on Cytokine mRNA expressions, and consequently, this suppression has a reasonable effect for DPB patients.