Left nostril breathing is not smooth right nostril is fine may be the left side of the nasal septum deviation, the left side of the nasal hemangioma, the left side of the turbinate hypertrophy, nasal polyps and other reasons. 1. Deviated left nasal septum: the structure of the nasal septum is biased towards the left side of the airway, so it leads to the left side of the nostril breathing is not smooth, and the right nostril is fine. 2. Left nasal hemangioma: the left nostril has a hemangioma blocking the airway, so the left nostril is not breathing well, and the right nostril is fine. 3. Left turbinate hypertrophy: there is rhinitis, due to the long-term stimulation of inflammation leads to the left turbinate hypertrophy, affecting the ventilation, so the breathing is not smooth, the right nostril is normal and fine. 4. Nasal polyps: the left side of the nasal cavity has polyps blocking the nostrils, resulting in the left nostril breathing is not smooth, the right nostril is fine. Left nostril breathing is not smooth, the right nostril is fine, there may be the left side of the nasal cavity, sinus tumors and other reasons, it is recommended to consult a doctor in a timely manner to identify the cause of the disease, for the cause of the treatment, so as not to miss the condition.