All About Mucus

You breathe in dirt, pollen, and other icky stuff. A slippery substance called mucus traps it all. Tiny hairs in your nose help move the whole glob toward your nostrils or to the back of your throat. Snot is that mix of mucus, dirt, and other stuff.

Your nose is a mucus-making machine. Every day, it churns out about 4 cups' worth. And you swallow most of it. It mixes with spit and passes down your throat without you even noticing. Sometimes the mucus gets too thick and it builds up in the back of your throat. When it runs down your throat, that's called postnasal drip.

Mucus shields you from stuff that could harm you. In your nose it keeps dirt, dust, and other harmful things that you breathe in from reaching your lungs. If that gunk got into your lungs, they could get infected or irritated, and you might have trouble breathing.

You don’t have to give up milk when you have a cold. It may make you feel like you have more phlegm, but studies show dairy products won't cause your body to make more mucus. That said, water, and lots of it, is the best thing when you're congested.

When it comes to mucus, the nose gets most of the attention. But you also have it in your stomach, intestines, mouth, and lungs. Thin layers of tissue that line the inside of your body make it. Mucus keeps things moist and helps protect you.

While a woman is pregnant, thick mucus forms a plug at the opening of her cervix and seals off her uterus, where the baby grows. When her body is ready for labor, the cervix opens wider and the mucus plug drops out of her body.

It does more than keep your breath fresh. Menthol, the main ingredient in peppermint, may help thin mucus. It can also help with some sore throats.

Usually, the mucus in your nose is clear. When you have an infection, your body sends in a bunch of white blood cells. These cells have a substance that can turn your snot yellow or green. But some of those white blood cells are always there, so you may still have green snot if you aren't sick. A blackish color may be due to dirt in your nose. Red or brownish boogers can be from broken blood vessels. A small amount of blood is usually nothing to worry about, but if it doesn't go away, call your doctor.

You may not like carrying tissues all winter long, but there's a good reason you need them. Your nose is doing its part to warm you. The small blood vessels in your nostrils widen to boost blood flow. This causes you to make more mucus, but it helps heat up cold air before it goes to your lungs.

A bad cold can make mucus build up in your lungs. Medications called expectorants make it thinner and easier to get out. Other cough medicines that do not have an expectorant won’t break up mucus. They just keep you from coughing.