Clear watery nasal discharge is usually manifested as allergic rhinitis, because patients with allergic rhinitis will have clear watery nasal discharge due to the high mucosal secretion function. If you find that your nasal cavity also flows clear water-like nasal mucus when you hold your breath with your head down, or when your head is tilted back or your neck is under pressure, you must go to the hospital to do CT or MRI of the nasal skull base to do imaging examination to determine whether there is cerebrospinal nasal fistula present. The treatment is as follows: 1, allergic rhinitis patients: for nasal runny nose, you can use anti-allergy medication to solve the problem; 2, cerebrospinal fluid nasal fistula: spontaneous patients can get better on their own through rest and do not need treatment; if the patient continues to run clear water-like mucus, surgery is needed after the diagnosis of cerebrospinal fluid nasal fistula.