Why Mucus Is Good

It’s slimy, stringy, and gross, but mucus is actually good for your health. 

Mucus (aka phlegm or snot) is slimy, goopy, and generally pretty gross. We put a lot of effort into getting it out of our body. Yet mucus is a lot more important to our health than we may realize.

The truth behind mucus

The 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 sounds disgusting, but mucus actually serves some important purposes.

“Mucus is multifunctional; our bodies produce mucus for our protection and well-being,” said Chicago allergist, Brian Rostkoff, 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. And like an air filtration system, mucus traps bacteria, viruses, and other tiny bugs in the nose and mouth before they can get into the body. Researchers have discovered mucus also fights off would-be foreign invaders. It’s armed with antibodies, as well as bacteriophage — 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 do 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 as to what’s going on 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 of the immune system, called neutrophils, go on the attack. These cells contain a greenish-colored enzyme, and 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, head of Public Health England’s Primary Care Unit. “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 it 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 work by shrinking swollen blood vessels in the nose, which leaves 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 the nose to swell up 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 the 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.