Why Do We Get Boogers?

It’s winter, and the temperature has been really strange. Up and down, up and down. One day I can walk around outside, thinking my light jacket is too much coat. Two days later, it’s snowing. It’s been that kind of season, and I think that’s why my son has the sniffles. He’s not sick, per se, but he’s sniffling and sneezing and his nose is running. So recently, he goes and grabs a tissue and wipes his nose. “Dad,” he asks, “why do we get boogers?”

Well, I did say I’d answer his questions…


What is a booger?

Let’s be honest here. You know what a booger is. You were a kid once, even if you haven’t been around any recently. Still, let’s do this right. Merriam-Webster gives two different definitions for the word “booger“:

  1. Bogeyman
  2. a piece of dried nasal mucus.

Clearly, in the contex of my son’s question, we’re talking about the second definition. I’ve never told him about the “bogeyman”, and I don’t think any of his friends have told him about that character. He’s six, and he’s feeling scared of the dark, so I think it would have come up if he had. So, let’s focus on the dried nasal mucus. The Online Etymology Dictionary gives the following explanation for the word

“nasal mucus,” by 1890s; earlier bugger. Also boogie.

So, yeah. No Greek or Latin or Proto-Indo-European here.

What is mucus?

Going back to Merriam-Webster, mucus is defined as “a viscid slippery secretion that is usually rich in mucins and is produced by mucous membranes which it moistens and protects”. It’s a fairly common fluid produced by the human body – heck, by nearly every animal, not just us humans. The respiratory system produces mucus in the nose, the airways (i.e. your sinuses and throat), and the lungs, as a way of trapping foreign particles. What foreign particles, you ask? Dirt. Dust. Bacteria. Pollen. Allergens. You name it, your mucus traps it. And the more your respiratory system needs to trap, the more mucus it produces. That’s why you generate more mucus (and then cough) when you get exposed to allergens or you get sick. Your body is trying to trap more of the foreign particles and expel them before they can cause you more problems.

Your respiratory system isn’t the only place that makes use of mucus, however. Your digestive system uses it for the whole length – from the esophagus into the stomach and the intestines and into the colon – as a way of lubricating your food in its journey through your body. It also shows up in the reproductive system, functioning as a lubricant and a means of transporting sperm and eggs through the body. Your eyes generate mucus as well, lubricating and protecting sensitive cells and keeping them moist.

So. How does mucous become boogers?

Bear in mind that mucus isn’t just water. It’s full of proteins and antibodies (because it isn’t just a passive defense) and electrolytes, not to mention all the dust and dirt and bacteria and such that it has trapped. As the water in the mucus evaporates or gets absorbed by the body, these solids get left behind, sticking and clumping together until – if not disturbed – they form masses of noticeable size.

I can’t believe I’m going to ask this, but… why the nose? Why not eye boogers?

Actually, those can happen. Eye crust, also known as rheum, is essentially eye boogers.

Great. Anything else?

Yeah. You know how your mom said you shouldn’t pick your nose and eat it?

Do I want to know this?

Hey, you’re the one still reading.

It turns out that there’s a hypothesis that boogers have a sugary taste that is meant to entice you to eat them. Because the act of doing so helps introduce weakened pathogens from the environment to your immune system, building up your defenses. This is rather controversial (not to mention nauseating), and it has not been tested. A number of scientists als point out that you swallow mucus all the time, just by living. This still serves to introduce the pathogens to your body. So don’t take this as a license to go to town on your nose, please.

I wasn’t planning to. Also, I hate you so very, very much right now.

Look, the human body is endlessly fascinating. Even the bits that we find culturally repugnant. Besides, you’re the one reading the article about boogers. What did you expect?