Nasal mucus is not phlegm in the lungs, due to nasal mucus produced in the nasal cavity, sinuses, and phlegm from the throat, trachea, and even the lungs, the two do not have too much connection. 1. Snot is often seen in the nasal cavity, sinus infection, leading to rhinitis, sinusitis formation, and stimulate the mucous membrane inflammatory reaction, and produce a lot of watery snot, white sticky snot, yellow pus snot. 2. Phlegm may be inflammation and infection in the throat, trachea, bronchus, and lungs, which makes the airway mucosa hyperreactive and produces inflammatory mediators, and stimulates the mucus cells to secrete a large amount of material to form phlegm. When there is a lot of nasal mucus, you can go to the relevant hospitals, under the guidance of the doctor to perform rhinoscopy or nasal CT or chest CT and other tests, in order to clarify the cause of the disease, early treatment of the symptoms.