In general, alternate nasal ventilation is a normal physiological response. If the patient has unilateral nostril breathing for a long period of time, it may be due to the presence of mucosal congestion, edema, exudation of inflammatory secretions, neoplasm and other manifestations of the opposite side of the nasal cavity, so that the nostril breathing is impeded, thus resulting in the emergence of uninasal breathing. If the patient long-term single nostril breathing, there may be deviated nasal septum, nasal polyps, nasal swelling, sinusitis and other diseases, may also be due to the posterior nostril stenosis, posterior nostril atresia, due to the different physical condition of the individual, the specific cause of the disease there are individual differences. It is recommended that patients go to the otolaryngology department of regular hospitals, through nasal endoscopy, sinus CT examination, etc., to clarify the diagnosis, and follow the doctor’s instructions for targeted treatment.