What Is Mucus? Surprising Facts About Your Boogers

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You may call it mucus, phlegm, boogers, snot, or something cutesy. Whatever you call it, there’s much it can teach you about your health.

During cold or allergy season, for example, it can seem like mucus is clogging up your sinuses, nose, and throat and just trying to ruin your life.

When you’re sneezing it out or coughing it up, mucus hardly seems like a good thing. However, mucus does have a purpose — and offers real benefits. Read on for useful facts about mucus that just might make you appreciate it.

What Is Mucus?

We associate mucus with our noses, but it’s so much more. It lines many of your body’s internal surfaces, including the respiratory, digestive, and reproductive tracts.

Mucus is a “viscous liquid,” meaning it’s thick and sticky. This consistency is crucial because it helps mucus trap dust, bacteria, and other foreign particles. This prevents them from entering your body and causing harm.

Our mucus glands, known as muciparous glands, make mucus. They line the mucus membranes of your digestive, respiratory, and reproductive tracts.

What mucus is made of is fascinating. It contains water, salts, antibodies, and antiseptic enzymes.

These enzymes inhibit the growth of or destroy harmful microorganisms, such as bacteria and viruses. They work together to maintain a healthy environment within the body.

Some of the ways mucus helps are by:

• Keeping food moving down your esophagus.
• Protecting your stomach lining against acid.
• Trapping dust, bacteria, and other particles in the air before they reach your lungs, acting as a first line of defense against infections.

Mucus is particularly important in protecting the respiratory system. “Phlegm” and “sputum” are common terms for mucus produced in the lungs and airways.

This particular form of mucus captures and clears out particles you inhale, keeping your airways clear and preventing infections. Additionally, the mucus layer in the stomach protects the lining from corrosive gastric acids, while in the esophagus, it helps food slide down smoothly.

Mucus keeps your airways moist and working correctly. This moisture allows mucus to trap harmful particles that you may inhale from the air. Mucus also contains enzymes or antibodies that can eliminate unwanted bacteria and viruses.

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Why Do I Have So Much Mucus?

Your body can typically produce a liter of this sticky stuff each day. If that sounds like you’re making too much mucus, understand it’s a normal and necessary process. This is true even if you often only notice it when things go wrong.

When you’re sick, your body makes even more mucus or thickens it. It ramps up mucus production as a response to the irritation and inflammation caused by invading allergens or pathogens. When the body produces too much mucus, you must expel it either by blowing your nose or coughing it up.

If inflammation affects the insides of your nose and sinuses, you may need more time to clear out excess mucus. So, when you’re sick and have more mucus, and it’s draining slowly, it may seem intolerable — but it’s important.

Just remember that sinus inflammation can increase pressure around the nasal area of your head and make blowing your nose more difficult or painful.

What Does the Color of Mucus Mean?

The color and consistency of mucus can offer valuable insights into your health. Normally, healthy mucus is clear, thin, and watery. It often goes unnoticed as it plays its protective role. However, changes in its appearance can indicate various conditions.

So, if you’re wondering what it means when your mucus is a different color, here are the answers:

• Brown or orange mucus — Dried blood or inflammation is the culprit causing this coloration. It often accompanies conditions that irritate the nasal passages, like a dry nose or certain chronic conditions.
• Clear mucus — When you’re healthy, mucus is typically clear and thin. It maintains moisture in the respiratory system and helps trap particles without drawing attention to their presence.
• White or cloudy mucus — This can signal a cold or the beginning stages of an infection. The cloudiness is due to an increase in immune cells responding to a viral infection.
• Yellow or green mucus — Bacterial inflection is likely the cause of this discoloration. It comes from dead white blood cells and other cellular debris accumulating as the immune system fights off the bacteria.

Rhinorrhea and rhinitis are common terms for a runny nose. Rhinorrhea is specifically the thin, mostly clear nasal discharge. Rhinitis is the inflammation of the nasal passages, which often results in a runny nose.

Understanding these variations can help you gauge when to seek medical advice. Talk to your doctor if you experience unusual mucus color changes along with other symptoms like fever or difficulty breathing.

Is Swallowing Mucus Bad?

Swallowing mucus might seem unpleasant, but it’s a natural process that’s generally not harmful. The mucus you swallow typically breaks down in your stomach, where stomach acids destroy its contents, including trapped bacteria and viruses. This process helps keep your airways clear and prevents mucus buildup.

Why Does My Mucus Smell Bad?

Bad-smelling mucus is alarming at times, but there’s often a reason for it. The smell can result from an infection, such as sinusitis, in which bacteria thrive and produce unpleasant odors.

Certain foods, medications, or medical conditions, like chronic sinus infections, can also cause mucus to have a distinct odor. If the smell continues or you experience other symptoms, like pain or fever, talk to your doctor to rule out any serious conditions.

Conclusion

Mucus might seem annoying, especially when there’s a lot of it. But it’s essential for keeping you healthy. It catches and gets rid of germs, keeps your body parts moist, and helps prevent infections.

Knowing what it does and how it can change helps you take better care of yourself and know when to see a doctor. If you’re feeling worried about your mucus because it looks, feels, or smells different, talk to a primary care doctor at UPMC.

Editor's Note: This article was originally published on January 25, 2018, and was last reviewed on December 5, 2024.

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