For a continuous runny nose, the best medicine depends on the underlying cause. If it is due to allergies, an over-the-counter daily antihistamine like Cetirizine or Loratadine is highly effective. Alternatively, a steroid nasal spray like Fluticasone can help reduce inflammation in the nasal passages. For safe, drug-free relief, you can use a saline nasal spray to flush out irritants. Please drink plenty of fluids to stay hydrated. If your symptoms persist for more than 10 days or are accompanied by a fever or facial pain, please consult a healthcare professional for a proper evaluation.