Nasal phlegm during inhalation may be related to nasopharyngitis, sinusitis, allergic rhinitis and other causes. 1. Nasopharyngitis: Inhalation of phlegm in the nose may be related to nasopharyngitis, because the nasopharynx is stimulated by inflammation, resulting in a large amount of secretion, which will cause the symptom, and may also be accompanied by a sore throat, nasal congestion and other symptoms. 2. Sinusitis: Sinusitis can easily lead to nasal discharge or pus flow, and there may be phlegm in the nasal cavity when inhaling. Sinusitis patients may also experience nasal congestion, dizziness, headache and other symptoms. 3. Allergic rhinitis: allergic rhinitis patients due to the nasal mucosa is stimulated, thereby secreting a large amount of nasal mucus, which will also lead to the patient inhalation nasal phlegm, may also be accompanied by sneezing, tearing and other symptoms. After the symptoms of inhalation of nasal phlegm, it is recommended to go to the regular hospital in time to carry out relevant examinations to determine the cause of the disease and then symptomatic treatment, so as to alleviate the physical discomfort.