You can get a runny nose (rhinorrhea) for a lot of reasons.

In most cases, it’s because of mucus buildup in your nasal cavity or sinuses due to a trigger or allergen. Your nose then fills up with excess mucus that drains through your nostrils.

But there are plenty of other triggers that might cause your nose to run, including your daily habits, your health, and even your meals.

Keep reading to learn why your nose might run when you cry, when you eat, when you’re cold, when you have a cold, and when you wake up first thing in the morning.

This one’s pretty straightforward. When you cry, tears drain out of your tear ducts — which are located underneath the lids of your eyes — and these tears pass into your nasal cavity.

There, they drip down the inside of your nose, mixing with mucus and any other substances in your nose like allergens or blood, and out through the openings of your nostrils.

So despite what you might think, the fluid running from your nose when you cry is not just snot — it’s tears and whatever else is in your nose at the time.

This reason’s got a fancy name: gustatory rhinitis, or nasal inflammation linked to a food reaction (but not a food allergy).

There are two types of runny noses you can get:

  • Allergic rhinitis. This type of runny nose happens when you’re exposed to allergens, such as pollen, dust, or even foods like peanuts, that create an inflammatory response.
  • Non-allergic rhinitis (NAR). This type happens when an irritant enters your airways and results in symptoms similar to those of an allergic reaction.

Gustatory rhinitis is a type of non-allergic rhinitis. It’s most commonly triggered by spicy food that causes your body to produce extra mucus. This happens when food stimulates receptors in your nose found on glands associated with mucus production. Extra mucus then drips out of your nose.

Some common foods that have been found to trigger this type of rhinitis include:

  • hot peppers
  • garlic
  • curry
  • salsa
  • hot sauce
  • chili powder
  • ginger
  • other natural spices

Your nose heats up and moisturizes the air you breathe into your lungs. This process destroys bacteria and irritants, as well as regulates air temperature in order to protect your lungs from damage by cold.

Cold air holds less moisture than warm air. So when you breathe it in, it can quickly dry out your airways and expose you to more irritants.

This stimulates your nasal tissues to create more mucus and fluid to keep your nose moist and protect your airways. Excess mucus and fluid then drain out of your nose.

When a cold virus enters your body, the body produces a substance called histamine, a compound that results in protective inflammation that also causes more mucus production in your nose.

This is beneficial for several reasons:

  • Mucus in your nose can help capture external irritants or bacteria that can get into your body and make you more sick while you’re dealing with a viral infection. The more mucus, the more irritants it can capture.
  • Mucus buildup acts as an extra layer of protection for your nasal tissue, preventing bacteria or viral matter from entering your body through your nasal cavity, sinuses, or blood vessels.
  • Mucus draining from your nose carries infectious bacteria and other irritants out of your body, helping reduce inflammation from exposure to both of these things.

Nose running symptoms can be at their worst in the morning because allergen and irritant exposure tends to be more severe at night.

As allergens build up in your airways overnight, your body has to work harder to clear them out when you wake up. This results in high levels of mucus production, which builds up in the back of your nasal passages while you’ve been lying down, and drains when you sit or stand up.

A runny nose doesn’t mean your sinuses are clearing out.

If your nose is producing extra mucus, you may not be able to clear it out enough to fully clear the mucus congestion in your nose and your sinuses, especially if it gets dried out.

And if you’re still exposed to the irritant, food, cold, or other cause of your nose running, your body will likely just keep producing mucus and fluid until you’re no longer exposed.

Here are some tips to help stop your nose from running:

  • Drink plenty of fluids. Being hydrated helps thin out mucus with extra fluid so that it drains more easily.
  • Drink hot tea, which has been found to help relieve cold and flu symptoms like a runny nose.
  • Try a facial steam. Fill a bowl or pot with hot, steaming water (not boiling!) and put your face into the steam for up to 30 minutes to clear your sinuses and nasal cavity of fluids and mucus.
  • Take a hot shower. The warmth and steam from a hot shower can help drain mucus from your nose.
  • Use a neti pot for nasal irrigation. Fill a neti pot with warm distilled water, put the spout in your nose, and tip it forward into your nostril to clear mucus, allergens, and debris.
  • Try eating spicy foods. Spicy foods can make blood vessels in your nose widen (dilate). This causes heavier drainage, which helps clear mucus and relieve sinus pressure.
  • Take capsaicin, a chemical in spicy peppers. It’s effective at treating congestion. Some studies suggest it’s better for a runny nose than medications like budesonide (Entocort).

A runny nose can be triggered by numerous things, and almost all of them have some kind of protective effect on the body.

But see your doctor if you have a constantly runny nose — you may have severe allergies or an underlying condition that needs treatment.