The article summarizes the modern data on the role of leukotrienes in the pathogenesis of allergic diseases of the respiratory tract, in particular, bronchial asthma in children. It determines the role of anti-leukotriene drugs in the treatment of these diseases, the perspectives and key indications for the use of Montelukast in children with bronchial asthma and allergic rhinitis. The article pays attention to highly effective generics, in particular Singlon®.