Think of the last time you had a cold and used a tissue to blow your nose—did you look at what was left inside?
Though not everyone will readily admit it, plenty of people take a sneak peek at the snot—or mucus—that comes out of their nose whether out of curiosity or disgust. What you may not realize, however, is how much your mucus can actually tell you about your health.
Mucus, while it may be kind of gross, plays an important role in your body.
“It’s part of your immune system, and it covers every inch of your body exposed to air that’s not protected by skin, including inside your nose,” explains Alison Grant, MD.
The sticky substance is an expert at trapping bacteria, viruses, dirt and dust, and keeping them from entering your body through your nose.
“If there’s an excess amount of germs present—such as when you have a cold—your body makes more mucus to trap the germs and get them out of your body,” says Dr. Grant.
Because of its important role, mucus can take on a different color if you’re experiencing an illness or other condition. In that case, it may actually be a good thing to take a longer look at what ends up in your tissue.
Mucus gives you a unique glimpse of your body’s health. Here’s a deeper look at how the color can reflect what’s going on inside of your body.
Why Your Snot Changes Color
Gross or not, snot is your friend. It helps your body stay protected, free of germs and healthy. And you make a lot of it—around 1.5 liters every day.
“The color of mucus comes from how it adapts to protect you, and that color can signal illness and other conditions,” explains Dr. Grant.
Clear Mucus
Your mucus is made of long molecules (called mucins) mixed with water. This forms a gel that usually stays clear. Most of the time, you won’t even notice mucus doing its behind-the-scenes job. However, if you start producing excess clear mucus, that may signify allergies due to your body trying to expel dust, pollen and other irritating particles.
White Mucus
If a virus makes its way into your nose and into the air-filled pockets behind your forehead, cheeks and nose—called the sinuses—your nose may start to make extra mucus to clear out the virus. After a few days, it might begin to turn white. This just means it’s doing its job in gathering up the enemy cells and escorting them out of your body.
Green or Yellow Mucus
One of the first signs of a cold is green or yellow mucus. It’s no reason for concern, and in fact, it means your body is working extra hard to fight off infection. White blood cells rush to battle infection, and when they’ve done their job, they get flushed out of the body along with the virus. The yellow color comes from dead white blood cells, which can turn green if there are a lot of white blood cells and other debris.
Red or Pink Mucus
Whether you keep blowing or rubbing your nose or you fall face-first onto it, blood is the primary reason your mucus can turn red or pink. It can also stick around your nasal cavity for a while, so lingering blood may just be a light shade of pink. Blood-producing irritation may not be so obvious, however, and it may be a result of something as simple as dryness in the air.
Brown or Orange Mucus
Dark mucus that looks brown or orange may cause you to panic, but one likely cause of it is simple: dried blood. It could also be a result of you inhaling something brown, such as dirt or cigarette smoke.
“The most serious cause of brown mucus is bronchitis, which is an inflammation of the tubes that bring air to your lungs,” explains Dr. Grant.
So, if you’re coughing up brown mucus, see your provider right away.
Black Mucus
Similar to brown mucus, dark, black mucus can be a result of inhaling something dark, such as cigarette smoke or dust. However, it may also be a symptom of a fungal infection, especially if your immune system is compromised, such as due to a disease like cancer.
The Reliability of the Snot Test and When to See Your Healthcare Provider
It’s always good to be aware of what’s going on in your body, including what comes out of it. If you notice a change in your mucus that concerns you, talk to your healthcare provider. Your healthcare provider has the power of medical training and diagnostic tests at their disposal, which go way beyond the snot test.
Also, if a mucus color change occurs alongside other symptoms, such as difficulty breathing, dehydration, pain or symptoms that last for more than 10 days, make an appointment to get it checked out.
The color of your snot can be a good indicator of illness or other conditions, and it’s one of your body’s many ways of communicating with you. Awareness is key—even when it comes to something as gross as your snot.