Why Mucus Is Good

By Stephanie Watson and Temma Ehrenfeld @temmaehrenfeld
December 04, 2023
Why Mucus Is Good

While mucus is slimy, stringy, and inconvenient, it actually is good for you, lubricating and protecting delicate tissue from drying out and cracking.

Mucus (aka phlegm or snot) is slimy, goopy, and inconvenient when you sneeze it or drip it. We put a lot of effort into getting it out of our bodies. But you should understand what mucus does for you.


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The truth behind mucus

Your mouth, nose, sinuses, throat, lungs, and gastrointestinal tract are all lined with mucus-producing tissue that churns out about a quart of the viscous stuff each day. That’s because it’s a good thing.

“Mucus is multifunctional; our bodies produce mucus for our protection and well-being,” says Chicago allergist, Brian Rotskoff, MD. “If we were to compare our bodies to cars, mucus would be the engine oil and air filtration system.”

Just like engine oil, mucus lubricates and protects the delicate tissue beneath from drying and cracking. Like an air filtration system, mucus traps bacteria, viruses, and other tiny bugs in your nose and mouth before they can get into your body. 

Researchers have discovered mucus also fights off would-be foreign invaders. It’s armed with antibodies, as well as bacteriophages — beneficial viruses that infect and kill harmful bacteria like E. coli.

You probably don’t notice mucus most of the time because it slides down your throat, along with the dust, germs, and other debris it’s collected. But when you come down with a bad cold or have an allergy attack, your body’s mucus production steps up. It thickens to the point where you start to notice and want to blow it out or cough it up into a tissue.

What that mucus looks like inside the tissue can give you an important clue about what’s happening inside your body.

What does mucus color mean?

Usually mucus is clear, but it can turn yellow or green if you have an infection. When you’re sick with a cold or other upper respiratory illness, white blood cells in your immune system, called neutrophils, go on the attack. These cells contain a greenish-colored enzyme. When a few million of them converge, they turn your mucus the same hue. 

Green or yellow snot alone doesn’t prove you have a bacterial infection, and it isn’t justification for an antibiotic prescription.

“It’s a prevailing myth that anyone with green phlegm or snot needs a course of antibiotics to get better,” said Cliodna McNulty, PhD, formerly a top official in the British health system. “Most of the infections that generate lots of phlegm and snot are viral illnesses and will get better on their own.”

Taking antibiotics won’t treat a virus, and doing so can contribute to the growing problem of drug-resistant bacteria.

What can you do about mucus?

If too much mucus bothers you, an over-the-counter cold and allergy medicine can thin it and dry it up. Decongestant pills and nasal sprays can shrink swollen blood vessels in your nose, leaving more room for air to flow through.

But you need to watch out for side effects, such as sleeping problems, nervousness, and high blood pressure. Don’t use nasal sprays for more than three days in a row because they can cause rebound congestion.

Antihistamines block a substance called histamine, which is triggered by allergic reactions and causes your nose to swell and release more mucus. Some antihistamines can make you drowsy, so be careful when you take them during the day. Other side effects include dry mouth, headache, and dizziness.

Guaifenesin thins mucus in your chest, making it easier to cough up and remove. Possible side effects are dizziness, headache, nausea, and vomiting.

A more natural way to clear out mucus is with a saline (salt and water) nasal spray or Neti pot, a small teapot-like device. When you spray or run saline through your nasal cavities, it washes away the mucus that’s been stuck up there.

Don’t go overboard trying to rid your body of mucus. Blowing or washing too much of it out will also flush out protective substances that could prevent you from getting sick the next time around.


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December 04, 2023

Reviewed By:  

Janet O’Dell, RN