The first common cause of bad smell in the nose is dryness. The mucous membrane in the nasal cavity has a layer of mucus blanket, which will make the secretions in the nasal cavity from front to back, from the nasal cavity to the nasopharynx, to the pharynx, and then discharge. If the nasal cavity is too dry, the mucus blanket will lose its function, and there will be some dust and dirty secretions in every corner of the nasal cavity. After a long time, it will produce a smelly nasal scab, emitting a smell, that is, ordinary people. Generally speaking, patients are advised to have nasal irrigation. There are many irrigators for nasal cavity irrigation in the market. You can buy these products online and in hospitals. If the nasal cavity still smells after washing, come to the hospital for a sinus CT to see if there are purulent secretions or sinusitis or even sinus tumors stored in the sinuses. After a CT scan of paranasal sinuses, 100% will show the nasal cavity and paranasal sinuses, which can explain why the nasal cavity smells and further treatment. Therefore, I hope everyone can go to the hospital for a sinus CT to explain why the nasal cavity smells.