Montelukast sodium is a leukotriene receptor inhibitor. In clinical practice, it is mainly used for spasm and contraction of bronchial smooth muscle caused by various reasons, as well as airway hyperresponsiveness, mainly to dilate the bronchi and improve the ventilation of the airway. It can generally be taken for a course of 1-3 months, depending on the severity of the patient’s condition. It is mainly used for the treatment of bronchial asthma, wheezing bronchitis, wheezing pneumonia and bronchitis caused by respiratory syncytial virus infection, as well as persistent irritant cough and eosinophilic pneumonia caused by Mycoplasma pneumoniae infection.