Sleeping at night and breathing through the mouth may be due to deviated nasal septum, chronic hypertrophic rhinitis, nasal polyps and other diseases, according to the different diseases need to choose the cause of treatment and symptomatic treatment to control the disease and alleviate the symptoms. 1. Deviated nasal septum: deviated nasal septum is an abnormality of nasal structure, along with chronic simple rhinitis due to gravitational factors can lead to nasal mucosal blood circulation obstacles, so that the nose sleeps at night without ventilation to breathe through the mouth, clinical treatment is mainly through surgical treatment, you can take the septum submucosal resection, or septum corrective surgery, and other measures for treatment. 2. Chronic hypertrophic rhinitis: chronic hypertrophic rhinitis can also lead to persistent nasal congestion, occlusive nasal sound, loss of sense of smell, etc., which can also cause the nose to sleep at night to breathe through the mouth. It can be treated by submucosal sclerosing agent injection in the inferior turbinate, as well as physical therapy measures such as cryotherapy and laser therapy, or by surgical treatment options such as partial resection of the mucosa of the inferior turbinate. 3. Nasal polyps: Smaller polyps have no clinical symptoms, but as the polyps increase in size, they may cause nasal congestion to worsen progressively, which may also cause the nose to be out of breath at night and breathing through the mouth. You can choose nasal glucocorticoid spray, such as fluticasone propionate nasal spray; conservative treatment is ineffective, you can take nasal polyp removal and other measures for treatment. If you are not able to breathe through your mouth at night, you need to go to the hospital in time for examination, to clarify the cause of the disease, and standardize the use of medication and treatment under the guidance of the doctor.