Where Does Snot Come From?

Today we examine an age old question.

Some people only seem to have mucus when they’re sick, but we’ve all seen the toddlers who sport an endless runny nose while running and playing and otherwise acting fine. At some point you can’t help but wonder, how is there so much of it and where does it all come from?
 

What exactly is it?

The fact is, mucus is actually a healthy and good thing! It’s like the oil that keeps your organs running smoothly.

It's a fluid made up of something called mucin. It generally acts as a protective layer over sensitive areas of your body. (6)

Although we tend to associate it with illness, there are mucosal glands throughout your body. They create new mucus all day long, more than a liter (4+ cups) per day! Usually you don’t even notice, and you swallow it right down the back of your throat like saliva. (2)

When it’s associated with your respiratory system, mucus is often called phlegm or snot, but there is mucus in other parts of your body too. (3) The cells that line your stomach, for example, secrete a type called gastric mucus, which protect your stomach lining from acids and other enzymes that help digest food. Without that mucus, you might have a terrible stomach ache most of the time. (5)

But a little snot goes a long way.

Sometimes allergies and other things in your environment can inflame the linings, called membranes, inside your nose. When that happens, your body thinks it needs to produce more protective mucus, causing an overproduction that leads to a runny nose. (1)

What else can cause your nose to run? I bet you know: crying. Your eyes have both tear glands and tear ducts. Just like the glands that produce mucus in your nose and stomach, the tear glands are what produce tears. When you cry, some of the tears spill onto your face, but some of them go back inside your body! They flow down into the tear ducts, which drain into your nasal passages, flushing out your nose so that all the snot comes running out. That’s also the reason why someone crying while lying down may cough or choke—some of the mucus drips down the back of their throat. (1)

So why do we have it? How does it keep us healthy?

Think about snot for a minute. How would you describe it? It’s often sticky, right? Like fly paper or scotch tape.

Mucus's job is to filter out all the gunk that shouldn’t get into your body, like cigarette smoke and pollen. (3) It’s also your body’s way of trapping and flushing out infection and microbes, which is why you produce so much snot when you’re sick. Unfortunately, sometimes this isn't helpful. Some people have a serious condition called Cystic Fibrosis, where their bodies create too much phlegm. (6)

True story: when I was young my family took a trip to an area where there was lots of smoking, and I suppose there was more soot and smog than I was used to. When I blew my nose at night, my snot came out black! That’s one way to tell it’s working, I guess...

So why do we call it snot? Turns out, the word developed a long time ago off of another word that you probably know: snout! Not only that, but there used to be an Old English word of similar origin just for the act of picking your nose: snite! (4) Isn’t that the best? I'm going to use it from now on.

Just remember, always use a tissue when you snite.
 

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★ Want to learn more? Check out these awesome resources that helped me write this little #Science article:

1. https://www.healthline.com/health/where-does-snot-come-from#crying-and-snot

2. https://www.livescience.com/54745-why-do-i-have-so-much-snot.html

3. https://www.bbc.com/future/article/20140321-where-does-snot-come-from

4. https://www.etymonline.com/word/snot

5.  https://teachmephysiology.com/gastrointestinal-system/stomach/mucus-production/#Gastric_Mucus

6. https://sitn.hms.harvard.edu/flash/2018/mucus-keeps-us-healthy/

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Jean M. Malone - March 2021