What Your Snot Can Tell You About Your Health

If you're feeling crummy, your mucus color can tip you off as to whether you're suffering from allergies or a viral infection.
Image Credit: PORNCHAI SODA/iStock/GettyImages

Whether you call it mucus, boogers, snot or, our favorite, a snot rocket, here's one thing you should know: That gooey, sticky, slimy material inside your nose is key to keeping you healthy.

In fact, think of it as your body's own natural moisturizer.

"Mucus is an important substance that the body produces to protect itself from foreign substances like viruses and bacteria," explains Philip Chen, MD, associate professor of otolaryngology/rhinology at the University of Texas Health Science Center at San Antonio.

"It protects the body in two ways," he says. "The first is as a physical barrier: Mucus is sticky and traps foreign particles, which the body can then sweep away like a broom. The second way is through its antimicrobial properties, as it is a water-based, sticky substance made of components like enzymes and antibodies that fight infection."

It should come as no surprise, then, that your nose produces on average a quart (or about 1 liter) of snot every single day. "Much of it is swallowed and we don't even know it," Dr. Chen says.

But during allergy season, or when you're battling a respiratory infection, it can seem like that mucus is clogging up your nose, leaving you stuffy, constantly blowing your nose and just generally feeling crummy. But again, this is a good thing.

"The body is purposely responding to the insult by increasing mucus to fight the infection and clear the body of it," Dr. Chen says. In other words, it may be annoying to have a drippy nose, but it's not harmful.

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What Your Mucus Color Means

Clear

Your mucus is made of long molecules (called mucins) mixed with water, says Anthony Del Signore, MD, an otolaryngologist and Director of Rhinology and Skull Base Surgery at Mount Sinai Union Square in New York City. So the default color is generally clear.

If you start producing a lot of clear mucus, though, it can signal allergies, and that your body is trying to get rid of particles like dust, pollen or animal dander.

In these cases, the best treatment is an over-the-counter nasal steroid spray like Flonase, along with using a saline nasal spray several times a day to help flush your nasal passages. If that isn't enough to give you relief, an OTC antihistamine like Claritin or Allegra can also help.

Tip

If you smoke, try to stop — the chemicals in smoke make it hard for your body to clear the mucus, which results in thick, stagnant gunk in your nose, Dr. Chen says.

White

White mucus means you probably have a respiratory infection like a cold.

When you have this type of infection, your nasal mucus will start out watery and clear, says R. Peter Manes, MD, a Yale Medicine rhinologist and sinus surgeon. But after a day or so, it thickens and turns white. This is because of an increase in proteins produced by infection-fighting cells called neutrophils.

Green or Yellow

Green or yellow mucus might appear several days into an upper-respiratory virus. The color comes from dead white blood cells, which can turn greenish if you have a lot of them.

While it's often assumed that green mucus means you have a bacterial infection like sinusitis, "the reality is most of the time this is just the normal course of a respiratory virus," Dr. Manes says.

Once your virus is vanquished, mucus will dry up and your nose will return to normal. But if it's really bothering you, a five- to 10-minute warm (not hot) steam can help thin out mucus and relieve congestion, Dr. Chen says.

You can also use a saline nasal spray, which helps soften and loosen mucus so you can blow it out more easily.

While an over-the-counter cold medicine that contains the ingredient guifenesin may help, "the evidence isn't great," Dr. Chen says.

You can skip OTC meds with the word "sinus" on them, which most likely include a decongestant such as phenylephrine. These may help you breathe more easily through the nose, because they decrease swelling in your nasal cavities, but they don't actually tamp down mucus production, Dr. Chen says. They're also not safe if you have high blood pressure and should not be used for a long time.

And while rubs like eucalyptus or menthol can be soothing to your schnoz, they won't decrease mucus production, either.

Resist the urge to call your doctor and beg for a prescription of antibiotics. "They don't benefit people with upper-respiratory tract infections like the common cold," Dr. Chen says. They also increase chances of antibiotic resistance, which means when you really do need to use them, they won't work.

When to See a Doctor for Green Mucus

If you have an upper-respiratory infection that lasts more than 10 days or gets worse after a week, see your doctor, Dr. Manes says. It may indicate that the virus has turned into a bacterial infection that needs antibiotics to treat.

You should also see your doctor if you have a fever over 103, or any fever that lasts for more than two days, or if your symptoms don’t respond at all to basic remedies such as saline rinses and OTC cold products.

Red or Pink

If you've been blowing your nose vigorously because you have a cold, it can cause irritation that leads to bleeding. This can stick around your nasal cavity for a while, causing mucus to be either light red or even pink, Dr. Del Signore says. The irritation can also be caused by dry indoor air.

If you have pink or red mucus, you can use a saline nasal spray or saline nose drops two to three times a day in each nostril to keep your nasal passages moist, Dr. Del Signore says. You can also run a humidifier in your bedroom at night to add moisture to the air.

Brown or Orange

Brown or orange mucus can be a sign of dried blood in your nose. It could also be the result of coming into contact with particles like dirt or cigarette smoke, Dr. Chen says.

"We as a society have been kind of trained to think color equals infection," he says. "Remember that mucus is meant to trap foreign particles, like dust or pollen. So a brownish tinge could just be a sign that your mucus is doing its job and doing irrigation."

Black

Black snot could indicate a fungal infection or exposure to a dangerous pollutant. See your doctor ASAP if you have black mucus.

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Is This an Emergency?

If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911. If you think you may have COVID-19, use the CDC’s Coronavirus Self-Checker before leaving the house.