Let’s learn about snot

Snot and other kinds of mucus play a crucial role in keeping us healthy

Sometimes snot might seem like your worst, and most disgusting, enemy. But it’s actually your friend — helping clear the source of irritation or infection out of your system.

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Snot gets a bad rap. It’s sticky and gross. And when you’re sick, it can stuff up your nose. But snot is actually your friend. It’s an important part of the immune system that keeps you healthy.

When you inhale, the snot in your nose traps dust, pollen and germs in the air that could irritate or infect your lungs. Tiny, hairlike structures called cilia move that mucus toward the front of the nose or the back of the throat. The mucus can then be blown into a tissue. Or, it can be swallowed and broken down by stomach acid. Swallowing snot might sound disgusting. But your nose and sinuses produce about a liter (a quarter of a gallon) of snot each day. Most of that slime slides down your throat without you even noticing.

Of course, allergies or a cold can kick your body’s mucus-making into overdrive. That extra snot can be annoying. But it helps your body flush out the source of irritation or infection. Inhaling tobacco smoke or getting water up your nose can trigger a runny nose for the same reason.

Mucus isn’t just found in the nose. This goop covers every part of the body exposed to air but not protected by skin. That includes the eyes, lungs, digestive tract and more. Like snot in the nose, this mucus keeps these areas moist. It also traps viruses, bacteria, dirt and other unwanted substances. Mucus in the lungs is called phlegm. If pathogens make it through your airways to the lungs, those pathogens can get stuck on phlegm. Coughing helps hack that phlegm up.

Other animals produce mucus, too. Some, like humans, use mucus to protect themselves. Hellbender salamanders, for instance, are coated in mucus that helps them slip away from predators. That led to their nickname: “snot otters.” This mucus also fights off fungi and bacteria that could make snot otters sick.

For other creatures, mucus is more of a weapon than a shield. Sea creatures called hagfish squirt mucus at predators to clog their gills. Some jellyfish use a similar tactic. They sling out globs of stinging snot for long-range attacks against other animals. Mucus may also help dolphins make the clicking noises they use to hunt down prey. However an animal uses their mucus, one thing is certain. The power of snot is certainly nothing to sneeze at.

Want to know more? We’ve got some stories to get you started:

Explainer: The benefits of phlegm, mucus and snot Mucus might seem gross, but it actually plays a key role in the immune system that keeps you healthy. (2/20/2019) Readability: 6.0

Snot may be key to dolphins’ tracking of prey Mucus may help dolphins make the chirpy clicking noises they use as sonar to catch prey. (5/25/2016) Readability: 7.9

Secrets of slime Hagfish shoot snotty slime at predators that is so strong, it could inspire new bulletproof vests. (4/3/2015) Readability: 6.0

Giant larvaceans have some pretty strange living arrangements. These sea creatures inflate “snot palaces” around themselves to net and filter bits of food drifting down from shallower waters.

Explore more

Scientists Say: Hagfish

Orca snot leads to a whale of a science-fair project

Making snotty scents

Ouch! Jellyfish snot can hurt people who never touch the animal

Good germs lurk in gross places

This tube worm’s glowing slime may help sustain its own shine

For coughing up phlegm, water is key

Ah-choo! Healthy sneezes, coughs sound just like sick ones to us

Hellbenders need help!

Chemicals from the world’s longest animal can kill cockroaches

Reversible superglue mimics snail slime

Activities

Word find

Ever wonder how far a sneeze can blow your boogies? A simple experiment uncovers the spray distances of different kinds of snot. Find the recipe for fake snot and instructions for the experiment in Science News for StudentsExperiments collection.

Maria Temming is the assistant editor at Science News for Students. She has bachelor's degrees in physics and English, and a master's in science writing.

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