It all begins with Mucus (say: MYOO-kus). This is the slimy sticky stuff that’s inside your nose.

Some people call it “snot”.

Your nose produces a lot of snot – up to a pint a day. But you swallow most of it.

While mucus may seem gross, it actually is very important and helps you stay healthy.

Your snot keeps germs dirt and bacteria from getting into your lungs. Kind of like an air filter as you breathe.

Sometimes your snot decides to wander and this is when you get a “runny nose”.

Here are the main reasons you may get a runny nose:

Cold or Flu.

When you have a cold or flu your nose is making extra mucus to prevent germs getting into your body.

Also, mucus is removing the virus or bacterial from your body.

So even though you’re already sick, you could get even sicker if it weren’t for the job you mucus is doing.

So when you have this extra mucus, and your nose feels stuffy, it’s a good idea to blow your nose into a tissue.


Kids with allergies get runny noses when allergies flare up, like when around pets or outside during pollen season.

This “runny nose’ reaction is the same as when reacting to germs – to protect your body from ingesting those particles that you’re allergic to.


When you cry, your tear ducts are working overtime.

Your tear ducts (which drain liquid in your eyes) are connected to your nose, so when you have a lot of tears, the liquid will mix with mucus and cause a runny nose.

Cold weather

When you’re outside on a cold day, your nose tends to be runny.


It’s trying to stay warm to warm up the air you breathe into your lungs.

Blood vessels in your nose open wider (they dilate) which help to warm up the air you’re breathing.

That extra blood flow causes more mucus production, so now your nose is runny.

Here’s The Fix!

The FIX is simple. If your nose is runny, blow your nose.

Then be sure to put your tissues in the garbage, away from other people. You don’t want to spread germs.

And remember, always wash your hands after you blow your nose!

To Health! 

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Kidcrew Medical

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About Dr. Dina Kulik MD, FRCPC, PEM

Dr. Dina Kulik completed her Pediatrics Residency and Pediatric Emergency Medicine Fellowship at the Hospital for Sick Children. Dr. Dina is one of Canada’s leading child health media experts, providing child health information through television, radio, print media, and via her blog Above all, Dina’s greatest joy is her family, and being the mom of four crazy boys.

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