How can you stop a runny nose?

Depends on the cause: A runny nose can be from allergies, a condition with reflexes causing a runny nose (vasomotor rhinorhea), a common cold, rarely head trauma can cause a leak of cerebrospinal fluid. Except for the leak, Ipratropium Bromide Nasal Spray is very effective for a runny nose. Allergies can respond to antihistamines, nasal steroid sprays or antihistamine sprays.