What Your Snot Can Tell You About Your Health

Your nose knows what's really going on.

It’s a perfectly human instinct to inspect our own bodily fluids for clues about what’s going on in there. You may know that your poop, pee, menstrual blood, and vaginal discharge can offer valuable intel about your health. But have you have ever blown your nose and immediately Googled something like "snot color meaning?" Yeah...us too.

Turns out, you actually can learn something from the drippy contents of your nose—and it’s not just the shade you need to pay attention to.

“Color is important, but so is consistency and amount,” Raj Sindwani M.D., an otolaryngologist at Cleveland Clinic, tells SELF. Here’s what should know about your snot—or nasal mucus, as the pros call it—and what it may mean.

First of all, what does normal snot look like?

Normal, healthy snot is clear, thin, watery, and plentiful, Erich P. Voigt, M.D., associate professor in the department of otolaryngology at NYU Langone Medical Center, tells SELF. "Our body produces about 1 liter of mucus and saliva a day, but we don’t notice the normal production." What’s the stuff made of? Mostly water, with some proteins, antibodies, and dissolved salts, according to the Cleveland Clinic.

Snot is also widely underappreciated, because it tends to fly under the radar until something goes wrong. "It's actually a really important part of our body," Dr. Voigt says. We would be much more susceptible to infection and irritation without it. “It’s a protector of our airways,” Dr. Voigt says. “Everything we breathe in gets filtered by that mucus.” This mucus both traps particles (like dust or smoke) and contains infection-fighting antibodies that kill off pathogens (like a virus or bacteria) we inhale before they have the chance to make us ill, Dr. Voigt says. Nasal mucus also moisturizes and warms up the air we breathe, so that it has just the right temperature and humidity and before entering our lungs, Dr. Sindwani explains.

So when nasal mucus is abnormal, it may indicate that something is up. Let's look at the rainbow of snot color meaning, shall we?

If your snot is clear, runny, and more abundant than usual...

A noticeable increase in the flow of pretty standard-looking mucus often means your nose is working overtime to try to get rid of something in there that your body doesn’t like, typically an allergen or irritant, Dr. Sindwani says. This is a classic symptom of seasonal allergies. "If it's the start of spring and all of a sudden your nose gets stuffy and starts running and it's clear," it's likely you're having an allergic reaction, Dr. Voigt says. This will typically be paired with other symptoms, Dr. Sindwani says, like itchy eyes or sneezing. Treating the allergic reaction with something like antihistamines should help stem the flow and clear up your other symptoms, but see your primary care doctor or an allergist if you’re feeling miserable every day.

Runniness that is sudden and short-lived can be due to other elements in the environment. You may be dealing with exposure to irritants, such as pollutants in the air, certain fragrances, or secondhand smoke, Dr. Sindwani says. Or, suddenly drippy discharge on a chilly day could actually just be water condensing as the cold air is warmed in your nasal passages and runs out your nostrils, according to the Cleveland Clinic.

Excess clear snot paired with other symptoms like a cough, fever, or general feeling of blahness that hangs around for three or four days may also signal the beginning a mild upper respiratory virus, like a brief cold, Dr. Voigt says. You can often treat yourself with OTC cold medicine, but see your doctor if you start to feel worse or don’t get better after a few days.

If your snot is cloudy and thick...

Colorless, thick nasal mucus (the kind that clogs up your nose and doesn't seem to budge no matter how much you blow) signals congestion that may be due to a couple things. One possibility is a chronic allergy, like if you're allergic to dust. "It’s everywhere year round, so you won't feel that runniness anymore, you'll just feel stuffy all the time and the nasal mucus might be thicker and more plentiful than usual," Dr. Voigt says. Consider seeing an allergist if this is the case for you.

Dehydration can also make your snot a little stodgy. “Mucus reflects the level of hydration in our bodies,” Dr. Sindwani says. When there’s less water content, it becomes more concentrated, viscous, and congesting. Thick snot may also make it seem like you’re got more snot in there than you actually do. "People who think they have too much mucus many times are, in fact, not making enough,” Dr. Voigt explains, “so it’s too dry and not flowing nicely." So if your snot is like molasses, drink up to help thin it out.

The third potential situation is that you’re at the very start of an infection that is causing the tissue in your nasal passages to become inflamed, slowing the movement of mucus through them, according to the Cleveland Clinic. Your mucus may even start to look a little white-ish at this point, Dr. Sindwani says.

If your snot is yellow or green...

The common wisdom here is true: yellow or green snot generally indicates that you have an infection. Any time your snot changes color, it means you have some sort of infection that has triggered an immune system response and increased blood flow to the area of inflammation. “There are infection-fighting cells that go to the site of this bug or germ,” Dr. Sindwani says. The concentration of these cells, such as white blood cells, can cause nasal discharge to appear yellow or green, he explains. The hue may also be due to an uptick in the enzymes these cells produce, according to the Mayo Clinic.

The idea that yellow equals one diagnosis and green another, though, is mostly a myth. “The color of mucus is not reliable in differentiating between a viral and bacterial infection,” Dr. Sindwani says. “Just the color, [doctors] don’t hang our hats on that. How you feel, your other symptoms, and how long it’s been around is also important.”

Generally, a shorter period of discolored snot and feeling crappy is more likely to be viral, while lingering infections are more likely to be bacterial. "If it's temporary and peaks in three to four days and gets better on its own, that can be due to a viral infection," Dr. Voigt explains, while longer illnesses that persist or worsen are more likely to be bacterial. This is when you should see your doc, who may typically need to prescribe antibiotics to get you healthy again.

If your snot is pink, red, or brown...

Although it may be alarming to find on your stark white tissue, a few specks of blood or a pinkish hue in your snot is actually no big deal. “This can happen whenever there’s been damage or trauma or irritation to the lining of the nose,” Dr. Sindwani explains, “and some tiny blood vessels may get broken.”

This damage often occurs when people are sick and blowing their nose too hard and too often, which can cause little tears in the membranes lining the inside of the nose—which are often already inflamed from fighting off infection, Dr. Sindwani says. It’s also pretty common in winter, when the air is super dry thanks to indoor heating, Dr. Voight explains. When those membranes get dried out, they’re more prone to crusting and cracking, causing bleeding.

Oh, and brown snot is kind of off-putting, but typically indicates old blood that has been chilling in there a while, Dr. Sindwani says. “Or maybe you breathed in some dirt.”

However, if you see a lot of blood in your snot frequently, or you get full-on nosebleeds on the reg, definitely see a doctor to rule out any major medical conditions. "It could be tumors in the nose or sinuses, but they’re rare," Dr. Voigt says.

If your snot is sticky, stinky, and discolored...

Some people suffer from chronic sinusitis, which makes nasal mucus very thick and glue-like, , green or yellow-colored, and even a little funky-smelling, Dr. Voigt says. “That foul odor is usually the smell of a bad infection or some dried-out crusty mucus that’s been hanging out in there a while,” Dr. Sindwani says.

A chronic [sinus infection can last for weeks or months at a time, according to the Mayo Clinic,) And icky snot is far from the only unpleasant symptom. You may also experience congestion, difficulty breathing, pain and swelling around the sinuses, and a bad cough. If you have abnormal nasal mucus that just won't clear up with time or antibiotics, consider seeing a specialist like an otolaryngologist (a ear, nose, and throat doctor) to figure out what's causing your symptoms.

If your snot is black...

If your mucus is the color of midnight, you’ve probably got a problem. Black mucus can be the result of smoking cigarettes or using illicit drugs, Dr. Sindwani says. Residual particles from the smoke and burning of the substance can turn snot dark.

The other possibility is a life-threatening fungal infection called acute fulminant fungal rhinosinusitis. However, this is exceedingly rare, Dr. Sindwani says, and usually only occurs in very ill people with compromised immune systems, such as cancer patients on chemotherapy. And often, the microscopic fungal spores are too tiny and few to be seen with the naked eye at all. Treatment involves emergency surgery and antifungal medication before the fungus invades the eyes or brain, per the Cleveland Clinic.