Pssst… your mucus is trying to tell you something about your health

It’s about that time of year again—the one in which snot seems to feature more prominently than it does in other seasons. (And yes, this article is about to be as sexy as it sounds!)

More formally, it’s mucus that we’re talking about here. Nina Shapiro, MD—author of Hype: A Doctor’s Guide to Medical Myths, Exaggerated Claims, and Bad Advice and professor of head and neck surgery at UCLA—describes the stuff as “a slippery material produced by mucous glands in the lining of the entire respiratory tract, including the nose, middle ears, sinuses, throat, trachea, and lungs.” While no one really has positive associations with phlegm, it’s actually a useful substance that serves to keep the tissue moist, while helping to clear bacteria, viruses, dust, pollutants, and allergens, she says.

Most of the time, it performs these functions in a low-key manner. You may have to clear it out from time to time—using a tissue and not your finger, because adulting—but it otherwise doesn’t call much attention to itself. Until it does, like when cold and flu season hits full tilt. A change in color or consistency is mucus’ way of telling you to pay attention—and, perhaps, to take action accordingly.

Keep reading to get the lowdown on what your snot is saying to you.

Clear

So, your mucus should be clear most of the time. However, Dr. Shapiro says that when it becomes visible (read: drippy), it can be a sign of allergies or a mild cold. Sometimes, she says, this even results just from being out in the elements. “Lots of people have runny noses with clear mucus when they’re outside in the cold,” she says. “In those cases, it is not a sign of illness.” Annoying, but NBD.

Yellow

Yellow mucus, on the other hand, can signal a cold. “If it’s yellow in the morning and turns to clear [as the day progresses], it’s probably a mild cold,” Dr. Shapiro says. In this case, she recommends using nasal saline irrigations or sprays, as well as sleeping with a humidifier at night.

You should, however, think twice about buying drugstore cold meds. “Oral, over-the-counter nasal decongestants can be hit-or-miss with any type of mucus—they can open up the congestion, but often have side effects such as thickening of mucus, jitteriness, sleepiness, or blood pressure issues,” the doctor adds. When using these, she advises getting your doctor’s advice, especially if you’re taking other prescriptions. (Including herbal or homeopathic remedies.)

Another reason to consider checking with your MD? In some cases, Dr. Shapiro says, thick yellow mucus can be a sign of a bacterial infection or a more significant viral infection. “This would need to be in the setting of other symptoms, such as fevers, deep cough, muscle aches, facial pain, or headache,” she explains.

Green

IMO, green is the worst color of the bunch. Why? “If the mucus is green, and you also have other symptoms such as fevers, cough, body aches, or headaches, it may be a sign of a sinus infection,” says Dr. Shapiro.

If this is your deal, she recommends nasal saline, rest, and use of a humidifier. “This may be a time to call your doctor to see if you might need an antibiotic,” she adds. “Sometimes the doctor will take a sample of the mucus for culture to see if there are bacteria warranting antibiotic treatment.”

Red

If your snot is red, Dr. Shapiro says not to freak out, even though it can be an indication of blood in the mucus. She tells me that when you’re blowing your nose a lot, the mucus lining can form little scabs that will turn the mucus a dark red or cause bright streaks of fresh blood. “If your nose is actually bleeding, you’ve probably been blowing it pretty hard… so take it easy,” she says.

Those of you who, like me, were prone to acute nosebleeds—as in, streams of blood coming from your nose rather than blood-streaked mucus—as a *super cool* child, may be surprised by Dr. Shapiro’s protocol. (I was doing it all wrong!) “For an acute nose bleed, pinch the nostrils closed, sit straight upright, and chew some ice chips,” she says. “OTC nasal decongestants and vasoconstrictors such as oxymetazoline and neosynephrine can help treat or prevent both nose bleeds and nasal congestion, but check with your doctor first.” Such meds, she says, should be used for no more than two days at a time. “If you use them long-term, they can create dependence and a rebound effect, making you even stuffier,” she explains.

To keep crusting at bay in the first place, Dr. Shapiro has a trick. “A little ointment in the nose—aqueous is best, such as Aquaphor—may help,” she says.

Brown

Brown mucus, says Dr. Shapiro, can be a sign of old blood or a bacterial infection, which is a sign you should check in with your doctor.

Got kids? If they have brown (or green or yellow) mucus coming from one side of the nose, it can be a sign of a foreign object stuck up there. “They will usually deny putting something up there, but the pediatrician needs to take a good look,” the doctor explains. “Illnesses usually involve both sides of the nose, so if it’s clearly one side only, they need to be checked.”

Dark (any color) with symptoms

Yellow, brown, green, red—it doesn’t matter, in this case. If it’s dark and accompanied by other symptoms, such as fever, coughing, headache, or facial pain, Dr. Shapiro advises a visit to your doctor.

Watery

Thin, watery mucus is usually a sign of allergies, a mild cold, or just being out in cold temperatures. “It’s the body’s way of filtering the stuff we breathe in,” says Dr. Shapiro. If your nose is dripping “like a leaky faucet” and is “as thin as water,” however, you may have a spinal fluid leak. This is very rare, she emphasizes, and is usually seen after sinus surgery. In this case, the leakage is usually on one side. She recommends—you guessed it—calling the doctor if that happens.

If you like playing detective, you’re in luck. Here’s what your period blood, poop, and nails can also tell you about your health.