Have the person sit down and lean his or her head forward. This will reduce pressure in the nasal veins and slow the bleeding.
Have them push the bleeding nostril firmly against the septum (the dividing wall in the nose). If the person is unable to do this, put on latex gloves and hold the nose for him or her for five to 10 minutes.
Once the nose stops bleeding, instruct the person not to blow his or her nose for several days. This could dislodge the clot and cause bleeding to begin again.