The main reason is that the secretion activity of the glands in the nasal cavity is enhanced, and the secretion increases, resulting in clear nasal discharge, which has the following main causes: 1, allergic rhinitis, which is one of the most common causes of clear nasal discharge, such as after contact with allergens, which can lead to acute allergic reactions in the nasal cavity, causing the glands in the nasal cavity to secrete excessively, resulting in the symptoms of increased nasal discharge. 2. Acute upper respiratory tract infection, especially the common cold, which is also called acute rhinitis in modern medicine, can cause inflammatory reactions in the nasal cavity, resulting in congestion and edema of the nasal mucosa and secretion of more nasal mucus, which can be relieved by using 3. If there is a ruptured cyst in the sinus, it can also cause the performance of running nose, which can be clarified by nasal endoscopy and sinus CT examination.