Some of the trials included children aged 6–24 months, which could incorporate some patients with post bronchiolitis wheeze [2, 13, 18]. This may have led to negative findings, because a Cochrane review reported that montelukast was not effective in reducing the incidence of recurrent wheezing, symptom-free days or relevant usage of corticosteroid in patients with post-bronchiolitis wheezing . Interestingly, two included trials that excluded children younger than 2 years showed significant improvements in montelukast group compared with placebo group [4, 15]. Subgroup analysis showed better outcomes for children 2 years of age and older (p = 0.017) . It is thus possible that there may have been some exaggeration of negative results due to the inclusion of children less than 2 years of age.