Menu Close

Curious Kids: why do I have boogies and why does my nose keep replicating them?

Is that what I think it is? Shutterstock.

Why do I have boogies and why does my nose keep replicating them? – Duncan, aged seven, Sydney, Australia.

Boogies, bogeys or even boogers – whatever you call them, the little bits of dry snot (or “mucus”) that form in your nose actually help protect you from harm.

Your nose makes mucus to help collect the tiny dust and dirt particles in the air you breathe, to stop them getting into your lungs.

The mucus also contains special molecules (with interesting names like “immunoglobulins” and “enzymes”) that help protect you against infection or break down the dirt that you pick up from the outside air.

Mucus is usually runny, but since you breathe through your nose (as well as your mouth) the air flowing through it will dry out some of the mucus and dirt. That’s what forms the little nuggets at the front of your nose you call “boogies”.

Curious Kids is a series by The Conversation, which gives children the chance to have their questions about the world answered by experts. If you have a question you’d like an expert to answer, send it to We won’t be able to answer every question, but we’ll do our very best.

An adult’s nose produces about 750ml of mucus every day – that’s about the same as ¾ of a carton of orange juice. That sounds like a lot, but most of it flows down inside the nose to the back of your mouth, where you swallow it without even thinking about it.

Cleaning machine

The mucus is produced by tiny little cells in the lining of your nose and sinuses, which are air pockets in your face.

Tiny little hair-like endings on the cells (called cilia) beat the mucus towards the back of your nose.

If you looked at the cilia under a microscope, you might see them all waving in the same direction.

Clear or colourful?

Mucus is normally clear, but you might have noticed that bogeys can come in different colours. Remember, your bogeys pick up particles in the air you breathe, so it’s normal for them to be different colours sometimes.

But if your bogeys are pink, red or brown, it might mean the inside of your nose is bleeding. And if your bogeys have a green or yellow tinge, it might be a sign that your body is fighting back against an infection.

Whatever colour they are, your bogeys are a sign that your nose is working to protect you.

Children can have their own questions answered by experts – just send them in to Curious Kids, along with the child’s first name, age and town or city. You can:

Here are some more Curious Kids articles, written by academic experts:

Want to write?

Write an article and join a growing community of more than 181,700 academics and researchers from 4,934 institutions.

Register now