8 Things Your Mucus Says About Your Health

Updated: Oct. 11, 2022

Mucus protects our body by trapping bacteria and particles. The color and texture of your mucus can give clues about your overall health.

Woman cough at outdoor

If your mucus is gray or black…

…you likely inhaled dark-colored particles, like smoke from a fire or heavy exhaust. Regular smokers can also blow out darker mucus because of the tar or other toxic byproducts they inhale, says Alfred M.C. Iloreta, Jr., MD, an otolaryngologist at The Mount Sinai Hospital in New York City. If you’re not a smoker, black mucus could mean a serious fungal infection, especially in people with compromised immune systems, according to Joseph Han, MD, Medical Director of the Division of Allergy at Eastern Virginia Medical School. Wondering why we even have mucus in the first place? Here’s the explanation plus: The science behind 9 other types of body gunk).

Close-up of black gorgeous woman fitness instructor drinking water during the training exercises in gym
Andrii Kobryn/Shutterstock

If your mucus is super thick and sticks in your throat…

…you could be dehydrated. Dehydration can cause mucus to thicken and coat the throat, making it feel sticky and dry, says Dr. Iloreta. Gulping down H20 will hydrate your body and the mucus should thin right out. Check out these other signs and symptoms of dehydration.

Runny nose. Ill young blond woman having fever and blowing her nose while having a blanket on her shoulders and sitting on the couch with her eyes closed and table with pills in front of her

If your mucus is yellow or green…

…you might have pneumonia, a sinus or throat infection, or another respiratory tract infection and your immune system is hard at work. “The green color comes from an overload of white blood cells fighting that infection,” says Dr. Iloreta. You’ll probably notice other symptoms, such as a cough or stuffy nose. Try these tips to relieve congestion.

Close-up mid section of a young woman with bleeding nose over white background

If your mucus is pink or red…

…you were bleeding or still are. Nasal tissue can break from dryness, impact, or some other sort of irritation (like your, um, finger). “A pink tinge is usually older blood, but bright red is a sign of active bleeding,” says Dr. Iloreta. If you consistently blow bloody snot into your tissue or cough it up, that’s cause for concern and you should see a doctor, he says. Here are the surprising reasons you could be getting nosebleeds.

young child with a runny nose
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If your mucus is clear…

…and medium consistency (not too runny, not too thick) you’re normal. If you feel it drip into the back of your throat or from the tip of your nose, it might be a sign of allergies, that you inhaled a bit of dust, or sinusitis if it’s accompanied by a headache or facial pain, says Dr. Iloreta. Or it may be vasomotor rhinitis, a condition some people experience when they encounter cold temperatures or eat spicy food.

brunette woman sneezing into a tissue

If your mucus is white and thicker…

…you’re getting sick, or are already there. You probably feel congested and are blowing your nose more often than normal. “Our immune system produces more white blood cells to fight the incoming infection, causing the mucus to thicken and turn white,” says Dr. Iloreta. When you’re sick, your nose tissue is swollen and inflamed, which slows the flow of mucus and makes you feel stuffy. Here are some more reasons you feel stuffy all the time.

Faucet with flowing water closeup

If your mucus is super runny…

…you could have a very rare condition called a cerebral spinal fluid (CSF) leak. This is when spinal fluid leaks through a hole in the skull bone and out into the nose or ear. “If it tastes salty and is as runny as water, it’s often misdiagnosed as an allergic reaction or seasonal allergies when in fact it’s a leakage of fluid around the brain,” says Dr. Iloreta. But don’t panic—while CSF leaks can occur spontaneously, they’re usually the result of trauma or surgery. Learn more about this condition here.

Portrait of woman 20s pinching nose with disgust on his face due to bad smell isolated over gray background
Dean Drobot/Shutterstock

If your mucus smells bad…

…you have some sort of infection. “A malodorous smell is most likely a sign of a sinus infection or upper respiratory tract infection,” says Dr. Iloreta. If your foul-smelling mucus is accompanied by cheek pain, it could also be a sign of a dental infection that spread to the cheek sinus, according to Dr. Han. Next, learn the different reasons your nose could be running all the time.

Reader's Digest
Originally Published in Reader's Digest