When you have a runny nose, there's usually a good reason for it. The mucus in your nose traps foreign objects (including germs) to keep them from entering your body and from reaching your lungs. So it's not always the best idea to stop your nose from running -- doing so might actually cause more harm than good [source: American Academy of Otolaryngology].

It's more important to treat the source of the runny nose than the symptom itself, so try to figure out what's causing your nose to run in the first place. Then you can easily take steps to prevent it.

  1. Did you just come in from the cold? Try to remember to keep your face insulated when you go out in cold weather.
  2. Did you come in contact with an allergen? Think about what you might be allergic to and try avoiding the potential allergen. You might have to see an allergist and get a prescription for an allergy medication.
  3. Do you have a cold? Make sure you get enough rest, nourishment and hydration to help your body fight it. If you deal with the cause of the runny nose, you'll end up treating the symptom as well, and this may prevent another runny nose in the future.

Although antihistamines won't cure a runny nose, no matter what the cause, they can provide some temporary relief. Prescription antihistamines take effect more slowly but have fewer side effects (like drowsiness and dry mouth) than over-the-counter antihistamines [source: American Academy of Family Physicians].

Some home remedies for a runny nose include chicken soup, ginger or onion tea [source: Food and Agriculture Organization of the United Nations] and spicy foods.