The Truth About Mucus

The Truth About Mucus 

Call it snot, call it mucus, call it a booger -- but don't underestimate what it does for you.

Mucus is something everyone has, and some people wish they had a lot less of the stringy, gooey stuff.  Sure, it can be gross to blow globs of snot into tissue after tissue when you have a cold or sinus infection, but mucus actually serves a very important purpose.

"Mucus is incredibly important for our bodies," explains Michael M. Johns, III, MD, director of the Emory Voice Center and assistant professor of otolaryngology -- head and neck surgery at Emory University. "It is the oil in the engine. Without mucus, the engine seizes."

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How much mucus is normal, and how much is too much? What does its color tell you about your health? Can you just get rid of it, or at least cut down on it, and how should you do that? Here are answers.

Mucus' Mission

Mucus-producing tissue lines the mouth, nose, sinuses, throat, lungs, and gastrointestinal tract. Mucus acts as a protective blanket over these surfaces, preventing the tissue underneath from drying out. "You have to keep them moist, otherwise they'll get dry and crack, and you'll have a chink in the armor," says Neil L. Kao, MD, associate professor of medicine at the University of South Carolina School of Medicine.

Mucus also acts as a sort of flypaper, trapping unwanted substances like bacteria and dust before they can get into the body -- particularly the sensitive airways. "You want to keep that environment, which is a sterile environment, free of gook," says Johns. "Mucus is kind of sticky and thick. It's got viscosity to it that will trap things."

But mucus is more than just sticky goo. It also contains antibodies that help the body recognize invaders like bacteria and viruses, enzymes that kill the invaders it traps, protein to make the mucus gooey and stringy and very inhospitable, and a variety of cells, among other things.

Why Am I Making So Much Mucus?

Even when you're healthy, your body is a mucus-making machine, churning out about 1 to 1.5 liters of the stuff every day. Most of that mucus trickles down your throat and you don't even notice it.

However, there are times when you do notice your mucus -- usually not because you're producing more of it, but because its consistency has changed.

"Typically, the mucus changes character. It gets thicker," Johns says. "When it has mass effect you feel it, and when you feel it, you want to hock." Some people just naturally have thicker, stickier mucus than others.

It generally takes a bad cold, allergy, or contact with something irritating -- like a plate of nuclear-hot Buffalo wings -- to throw your body's mucus production into overdrive.

For instance, during an allergic response to an offending trigger, such as pollen or ragweed, mast cells in your body squeeze out a substance called histamine, which triggers sneezing, itching, and nasal stuffiness. The tissue of the mucus membranes starts leaking fluid, and your nose begins to run.

Drinking milk may also make some people produce more mucus. Kao says that's due to gustatory rhinitis, a reflex reaction that's triggered by eating. Gustatory rhinitis is also why your nose runs when you eat hot peppers. Milk proteins cause the same type of response in some people. But although you may feel like you have more phlegm, you're not going to worsen a cold by drinking a glass of milk,.

Why Does My Mucus Change Color?

If you've ever stopped to look at the contents of the tissue after you've blown your nose, you may have noticed that your mucus isn't always perfectly clear. It may be yellow, green, or have a reddish or brownish tinge to it. What do those colors mean?

You might have heard that yellow or green mucus is a clear sign that you have an infection, but despite that common misperception, the yellow or green hue isn't due to bacteria.

When you have a cold, your immune system sends white blood cells called neutrophils rushing to the area. These cells contain a greenish-colored enzyme, and in large numbers they can turn the mucus the same color.

But "you can have perfectly clear mucus and have a terrible ear and sinus infection," Kao says. If you do have an infection, you'll likely also have other symptoms, such as congestion, fever, and pressure in your face, overlying the sinuses, Johns says.

Multi-hued mucus also relates to concentration of the mucus. Thick, gooey mucus is often greenish, Kao says.  

Mucus can also contain tinges of reddish or brownish blood, especially if your nose gets dried out or irritated from too much rubbing, blowing, or picking. Most of the blood comes from the area right inside the nostril, which is where most of the blood vessels in the nose are located. A small amount of blood in your mucus isn't anything to worry about, but if you're seeing large volumes of it, call your doctor.

How Can I Get Rid of Mucus?

People with chronic sinus problems who are constantly blowing their noses understandably want the goo gone. Over-the-counter antihistamines and decongestants are one way to do this. Decongestants cause the blood vessels in the lining of the nose to narrow, reducing blood flow to the area, so you're less congested and you produce less mucus.

Decongestants are fine for when you can't breathe due to a cold, but they're not so good for thick mucus in general. "The reason is the decongestants dry you up and they make the mucus thick, and often the opposite effect happens because you feel like you have thick mucus," Johns explains. So you take more decongestants and get into a vicious mucus-producing cycle. Decongestants also have side effects, which include dizziness, nervousness, and high blood pressure.

Antihistamines block or limit the action of histamines, those substances triggered by allergic reactions that cause the tissue in the nose to swell up and release more, thinner mucus (a runny nose). The main side effect of older antihistamines is drowsiness. They also can cause dry mouth, dizziness, and headache.

You can also thin out the mucus with guaifenesin, a type of medicine called an expectorant. Thinner mucus is easier to get out of the body. Possible side effects of guaifenesin are dizziness, headache, nausea, and vomiting.

Neti Pot Option

If you want to go a more natural route, an alternative for removing mucus is with nasal irrigation. The neti pot, a little teapot-shaped device, is one form of nasal irrigation. Others include the bulb syringe or squeeze bottle.

Every nasal irrigation method works by the same basic principle: You shoot a saline (salty water) solution up one nostril to loosen up all the mucus that's collected in your nasal cavity, which then drains out the other nostril. It's similar to cleaning gunked-up food off a dinner plate in the dishwasher, Kao says.

According to the CDC, if you are irrigating, flushing, or rinsing your sinuses, use distilled, sterile, or previously boiled water to make up the irrigation solution. It’s also important to rinse the irrigation device after each use and leave open to air dry.

Nasal irrigation is a good thing, but as the old saying goes, it is possible to have too much of a good thing. Rinsing out your sinuses washes out the bad, nasty bacteria and other critters that can cause infection. However, one study showed that when people do it too often, nasal irrigation might actually increase the risk of infection because it also washes away some of the protective substances that help prevent you from getting sick. So use your neti pot or other nasal irrigation device when you need it, but take a break from it when you feel better.