Taking montelukast sodium usually 2 hours can play an anti-allergic effect, the half-life of the drug is about 2~5 hours. Montelukast sodium belongs to the selective cysteinyl leukotriene receptor antagonist, clinically can be used for allergic rhinitis, bronchial asthma and other patients’ treatment, two hours after oral administration of the drug can reach the highest blood concentration, to play an anti-inflammatory and anti-asthma attacks, the drug’s half-life can be up to 5 hours, most patients can take once a day. Montelukast belongs to the western prescription drugs, the adverse effects of the drug are depression, drowsiness, abdominal pain, diarrhea, nausea, vomiting, edema, fatigue, joint pain and other symptoms, allergic to the components of the drug is prohibited. Clinical use of Montelukast should be under the guidance of a physician, choose the appropriate indications, and pay attention to the adverse effects of the drug.