When one nose is not ventilated during sleep, there are often two situations: first, alternating nasal ventilation; second, only one side of the nasal cavity is not well ventilated. If it is alternating, mostly due to chronic simple rhinitis, which is mainly related to cold, cold, like smoking and drinking, eating spicy, and at the same time can be applied nasal spray drugs, such as co-solvadex or endosolvadex, with rhinitis drugs, such as cantharis rhinitis drops or nasal inflammation capsules. If one side of the nose is ventilated, consider whether sinusitis and nasal polyps, deviated nasal septum or nasal tumors lead to poor nasal ventilation, to be under the fiberoptic nasopharyngoscope for a clear diagnosis.