Guide

Why does your nose produce so much snot when you have a cold?

3/1/2025

Translation: Katherine Martin

When you have a cold, the endless stream of snot coming out of your nose is almost as aggravating as having a sore throat. But nasal mucus isn’t just an annoyance – it has an important function too.

«Something’s going around.» Chilly winter days are upon us, bringing a whole host of cold viruses along with them. These uninvited, unwanted «guests» come bearing gifts, one of which is a boatload of snot.

Slime is all the rage with kids right now. But the yellow version produced by your nose? Not so much.
Source: Shutterstock

What is snot and what does it do?

Basically, every cavity in your body’s covered with mucous membranes. These membranes self-regenerate, keep surfaces moist and protect your body from intruders. That’s where mucus comes in. Produced by glandular cells, it’s released via the cilia on mucous membranes. It’s a viscous, water-based gel, mostly made up of salts, glycoproteins and lipids (linked article in German).

Foreign bodies are flushed away with the mucus.
Source: www.husten.de/hustenloeser-wirkweise.html

When you’re well, the glandular cells in your nose and throat continuously produce an appropriate amount of mucus (linked article in German). This keeps mucous membranes moist and acts as a natural barrier, stopping dirt and pathogens from getting into the body. When someone sneezes on you or when you walk through a cloud of dust, foreign bodies land on the cilia of your mucous membranes. They get stuck and are transported by mucus towards your throat, where they’re swallowed. This natural protective mechanism stops any nasty intruders from getting into your lungs.

What happens if you have a cold?

Dry air, a cold nose, smoking, a lack of fluids or simply a weakened immune system can impair the mucous membrane’s defensive mechanism. This makes it easier for pathogens to settle into the body and trigger inflammation. In response, your body increases mucus production to flush away the germs. If this isn’t enough, your body’s own defensive cells are activated too. These fight viruses and bacteria, turning your mucus viscous and giving it a greenish or yellowish colour. Later on, you develop a cough too – all with the purpose of getting rid of foreign bodies trapped in your mucus as quickly as possible.

The inflammation means it can take two to three weeks after initial infection until the swelling in your mucous membranes goes down and mucus production goes back to normal.

How to prevent the common cold

You won’t be able to avoid getting the cold completely. However, if you know how mucous membranes work, you’ll be able to spare yourself the worst of it. Contrary to popular belief, colds don’t develop as a result of low temperatures or draughty rooms alone. They always involve pathogens transferring from person to person (linked article in German). Dressing warmly won’t be much good if you end up making out with your cold-infested crush on a polar bear rug in front of the fire. In fact, numerous studies (in German) have demonstrated that cold temperatures aren’t to blame.

However, increased infection rates in winter are thought to be related to nasal mucosa. When temperatures plummet, the nasal mucous membrane is less well supplied with blood and gets quite dry (linked article in German). This reduces the number of defensive cells in the nose, making it easier for cold viruses to penetrate the tissue.

With this in mind, try to drink enough water to keep your upper airways sufficiently moist (moisture is a key component of mucus). You should also breathe through your nose, as this preheats the air and filters a large number of particles out. If your throat still feels scratchy and dry, putting a humidifier in the room will help. Steam inhalation also restores moisture to the mucous membranes. Smoking (who’d have thought it?) puts your natural defence mechanisms under strain. Smoke particles overwhelm the mucous membranes, creating ideal conditions for germs.

Tissues

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Have you caught a cold despite your best efforts to keep your mucus healthy? If so, my colleague Anne Sandner has some good tips for you.

Guide
The common cold is all around – what helps and what’s useless
by Anna Sandner

Header image: Shutterstock

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Stefanie Lechthaler

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Stefanie.Lechthaler@digitecgalaxus.ch

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