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Winter weather often brings a lot of noticeable snot, but what does it tell us about our health?

Donna Coutts, June 12, 2019 7:00PM Kids News

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Ruby has a cold. Her nose won’t stop running. Picture: Alex Coppel media_cameraRuby has a cold. Her nose won’t stop running. Picture: Alex Coppel


Reading level: green

We all make about 1.4 litres of snot every day, whether we’re sick or healthy. Yuck.

We swallow most of it. Double yuck.

Not many of us know much about snot — also called mucus — because it’s not a very nice thing to talk about.

And most of the time, we don’t notice that we’re making and swallowing it.

But when we’re suffering from an allergy, a cold or the flu, there seems to be so much snot we can feel like we’re drowning in it.

We’re not. We don’t produce any more snot when we’re sick than we do when we’re healthy. It just changes to become thicker or runnier and those changes are noticeable and make us feel uncomfortable.

media_cameraWe mostly don’t notice mucus unless there’s something wrong and the balance of mucus and watery liquid isn’t how it should be. Picture: iStock

Here are a few of the most important things you’ll need to know to become your own snot detective. And be sure to leave everyone else’s snot alone.

Doctors and people who don’t like saying snot call it mucus.

Mucus is a sticky substance made in your nose and sinuses. The sinuses are a series of hollow sections in your skull, above and beside your nose.

Mucus is made to filter air before it goes into your lungs. Dust, pollen, smoke and other polluting things stick to the mucus.

Nasal epithelium - the mucus-coated lining of the nose traps odoriferous particles and hair-like structures called cilia transport them to the olfactory centre at the top of the nasal cavity. (Pic taken from book "Inside the Body: fantastic images from beneath the skin") media_cameraA view with a microscope of the inside lining of a nose, with hair and gloopy mucus visible. Picture: from the book “Inside the Body: fantastic images from beneath the skin”

Its other job is to lubricate or moisturise the inside of your nose, throat, lungs and digestive system* to stop the surfaces drying out and cracking.

What most of us think of as snot is actually a mix of two things: mucus and a more watery secretion*.

When we’re healthy, the body produces just the right mix of mucus and the watery secretion for the best moisturising and filtering results.

If you are allergic to something — for instance, if you get hayfever — your body makes more of the watery secretion to help wash or flush out the allergens* you have breathed in and your nose drips like a tap.

Sometimes when you have a cold your nose blocks, your throat feels dry and the snot is very claggy. This is usually because where the watery secretion is made is inflamed* and you’re not making enough of the watery secretion to get the balance with mucus right.

Chill - Step 2 - Hand stirring finished fake snot. Fake Snot recipe from children's book "The Surfing Scientist: 40 Super Human Body Tricks" by Ruben Meerman. media_cameraWhen there is not enough watery liquid mixed with mucus in your snot, it becomes very claggy. This is fake snot. Picture: from the book “The Surfing Scientist: 40 Super Human Body Tricks” by Ruben Meerman

Phlegm is a slightly different substance to the mucus made in your nose and sinuses. It is made in your lower airways and lungs. It is made when there is inflammation*, often in response to an infection. When we cough up a snot-like substance, it is often phlegm.

Snot, mucus or phlegm can be clear, white, yellow, green or brown.

Looking at the colour of your snot or phlegm is interesting, but it may not give you a very accurate answer about your health.

If it is yellow, green or brown it could be a sign that your body is fighting an infection such as a cold, but you can have an infection and still have clear or white snot. How you feel is a much better guide to your health than snot colour.

BCM SUPPLEMENTS 7/12/2012. Amy Ingram, Nick Skubji & Nelle Lee of the Shake and Stir theatre company will perform Out Damn Snot. Photographer: Liam Kidston. media_cameraAmy Ingram, Nick Skubji and Nelle Lee were actors in a play called Out Damn Snot. Thankfully, they are covered in fake snot. Photographer: Liam Kidston

Sometimes, the colour can be just because there has been a lot of dust or smoke in the air and the snot has done its job filtering the air before you breathe it.

Colds and other viruses such as influenza — also called the flu — are contagious and spread by droplets of snot or spit (called saliva). You can do a lot to keep yourself and others healthy by:

  • Keeping your hands out of your mouth
  • Washing your hands before you eat and after you blow your nose
  • Not sharing cups, drink bottles, plates and cutlery
  • Sneezing or coughing into a handkerchief or tissue or well away from everyone else
media_cameraSneezing without covering your mouth spreads your germs out for everyone else to catch.

A cold is a minor infection that should clear up by itself in 7-10 days. You don’t usually need to go to a doctor when you have a cold.

Common flu symptoms include a sudden fever (high temperature), body aches, extreme tiredness and a dry cough. People who have the flu may also feel unusually cold (called the chills), have a sore throat and a runny or blocked nose and not feel hungry.

If you think you or someone in your family has the flu, rest, drinking enough water and generally looking after yourself or them is important.

It’s also important if you think you have the flu to stay away from other people — particularly babies and people who are sick or elderly — to prevent spreading the infection.

Cold and flu what you should do

The Australian government and doctors recommend getting a flu vaccine each year.

The vaccine provides a high level of protection from the flu so that you are much less likely to be infected or you get only a very mild dose.



  • digestive system: series of organs that digest food, including mouth, oesophagus, stomach and intestines
  • secretion: a substance discharged or let out from a gland, cell or organ
  • allergens: things that cause an allergic reaction
  • inflamed: swollen
  • inflammation: swelling


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  1. What are the two main jobs of mucus?
  2. Does the colour of your snot tell you exactly what is wrong with you?
  3. What can you do to prevent the spread of infection?
  4. Name three common symptoms of the flu.
  5. Is it possible to get the flu if you have had a flu vaccine?


1. Have Your Say!
“This story is disgusting! Kids News shouldn’t have stories about snot, it’s wrong.”

Write a text that will persuade the person who wrote this sentence to understand why it is important for kids to learn about “yucky” or unpleasant things, especially snot.

Time: allow 20 minutes to complete this activity
Curriculum Links: English, Science, Health and Physical Education

2. Extension
“It’s Snot Yucky!”

Create a script for a TV, radio or online ad. The purpose of your ad is to help people understand how snot, phlegm and other kinds of mucus play an important role in our bodies and for our health.

Time: allow 45 minutes to complete this activity
Curriculum Links: English, Science, Health and Physical Education, Media Arts, Critical and Creative Thinking

After reading the article, with a partner, highlight as many connectives as you can find in pink. Discuss if these are being used as conjunctions, or to join ideas and create flow.

HAVE YOUR SAY: Have you or a family member had the flu? How was it different to a cold?
No one-word answers. Use full sentences to explain your thinking. No comments will be published until approved by editors.

Extra Reading in explainers