Our primary goal was to determine whether LTD4-BPT could be a clear indicator for assessing efficacy of LTRA. Logistic regression model was adopted for statistical analysis. In this model, pre-treatment PD20FEV1-LTD4 represented anticipated efficacy. The median of PD20FEV1-LTD4 was used for classification of asthmatics, with a lower figure representing a better anticipated outcome. Various variables, including the difference in pre- and post- treatment FENO, PEFmax, PEFmin, PEFR, PD20FEV1 and asthma scores, were introduced in the model representing the actual efficacy of LTRA. We aimed to test whether there would be certain parameters that assist prediction of anticipated outcome.