The main cause of nasal inaeration after a cold is the increased secretion of glands in the nasal cavity after a cold, resulting in a large amount of secretion and causing nasal inaeration. After a cold, the mucous membrane of the nasal cavity becomes congested and edematous, resulting in narrowing of the nasal cavity and causing poor nasal ventilation. If the symptoms of poor nasal ventilation occur once you have a cold, you can consider using medicines for rhinitis, such as nasal anti-allergy sprays, such as endosulfan or rhinocort, while treating the cold. If the effect of the spray alone is not good, you can also use decongestants for the nasal mucosa, such as ephedrine hydrochloride nasal drops or furacilin nasal drops, but when using decongestants for the nasal cavity must not exceed 10 days, otherwise it will easily cause drug rhinitis.