What does the color of your nasal mucus mean?

Whether you refer to nasal discharge as mucus, phlegm or snot, you probably also call it “gross.” This slimy substance certainly isn’t pleasant. But the mucus that lines the inside of your nose and other parts of your body plays a very important role in keeping you healthy.

“Mucus traps bacteria, viruses and allergens before they spread throughout your body and make you sick,” says Chiraag Patel, MD. He is an allergy specialist at Granite Bay Allergy, Asthma and Immunology in Roseville, California. “And if you do get sick, the color of your mucus can sometimes provide a clue about the type of illness you have.”

Of course, doctors will also look at your other symptoms, such as fever and tiredness, to make the right diagnosis, says Chau B. Nguyen, DO. He is an internal medicine doctor who practices at Austin Regional Clinic in Georgetown, Texas: “But just the fact that the color of your mucus has changed means your body is reacting to a foreign invader,” he says.

Read on to learn what the color of your mucus may be telling you about your health.

Mucus color: Clear

Normally, mucus is clear and thin, which makes sense considering it’s mostly water. But it can also be clear if you’re battling allergies. “If it’s allergies, you’ll notice more mucus than usual, which can make your nose congested and runny,” says Dr. Patel. The excessive mucus can also cause post-nasal drip, which is mucus that drains down the back of your throat.

An increase in the amount of clear mucus can also happen at the beginning of a cold or other viral infection.

Nonallergic rhinitis, which causes symptoms similar to allergies, is another possible culprit. According to the Asthma and Allergy Foundation of America, this can occur when you’re:

• going through hormonal changes (such as when you’re pregnant)
• overusing nasal sprays
• exposed to irritating substances such as smoke

Mucus color: White

Seeing white or cloudy mucus occasionally isn’t unusual and may not be a reason for concern. But it can be a sign that you have an upper respiratory tract infection, such as a cold, flu or COVID-19.

“White mucus gets its shade from the white blood cells and proteins in it that fight off invaders such as viruses,” Dr. Patel says.

Cloudy or white mucus is thicker than normal, due to the congestion caused by an illness, which slows down the flow of mucus. As a result, the mucus loses moisture and gets thicker.

(Think you might have COVID-19? Check out our COVID resource center.)

Mucus color: Yellow or green

You may have heard that these mucus colors mean you have an infection, and that’s often the case. “Yellow or green mucus appears at the peak of an infection, which occurs 3 to 5 days into an illness,” Dr. Patel says.

Yellow or green mucus signals a normal part of fighting an infection. Mucus can look yellow due to the rush of white blood cells that are sent to the infected areas of the body. These white blood cells produce enzymes to battle invaders — and those enzymes contain iron that turns the mucus dark yellow or green.

If you have a cold or flu, you should start to feel better in 7 to 10 days, at which time your mucus should be back to its normal color or close to it, Dr. Patel says.

But if you still have symptoms of your illness and your mucus is still yellow or green after those 7 to 10 days, make an appointment to see your doctor. You may have a bacterial infection that needs to be treated with antibiotics.

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Mucus color: Pink or red

Mucus that’s pink or red is usually nothing to worry about. Those colors may appear if your nasal tissue has become dry or irritated. Nosebleeds and injuries to the nose are other common causes.

“You may also have pink or red mucus due to coughing, sneezing or blowing your nose a lot,” Dr. Patel says. “The force that’s created can tear tiny blood vessels in your nose and throat and cause a little bit of bleeding.”

If your nose is dry or irritated, try running a humidifier and using a saline spray. Both of these strategies can help moisturize and soothe your nasal passages.

Mucus color: Orange or brown

Mucus may turn orange or brown if it contains dried blood, but the more likely explanation is that you inhaled something orange or brown, such as dirt, paprika or snuff.

Woodworking and drywalling without a protective mask can also cause brown mucus, Dr. Patel says. Smoking cigarettes can turn mucus brown as well.

Mucus color: Black

Inhaled substances, such as smoke and pollutants, can turn your mucus black temporarily. But if you have chronic black mucus, call a doctor. It can be a sign of a serious fungal infection in the lungs.

“Fungal infections make you very ill, and they need to be treated right away,” Dr. Nguyen says. “They’re not very common, although certain people are more likely to get them, such as those who have diabetes.”

Additional symptoms of a fungal infection in the lungs include shortness of breath, fever, chest pain and coughing up blood.

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Additional source
Rhinitis symptoms: Asthma and Allergy Foundation of America (n.d.). “Rhinitis: Nasal Allergies”