You may think of mucus as something that builds up in your sinuses, throat and chest when you’re sick, but it’s more than that. Mucus is a natural part of your immune system, and can be found in your nose, mouth, throat, urinary tract and digestive system. Your body is always making mucus (about 1-2 liters a day) as a way to keep you safe.

When you’re feeling well, you won’t even notice how mucus is working behind the scenes to keep you healthy. But if your mucus needs to work extra hard, you will probably know.

When your body is fighting against an infection, illness, irritants or allergens, your mucus goes through changes. You might cough up thick yellow phlegm, see hard nasal mucus on a tissue or even notice cloudy mucus in your urine.

Mucus changes are often good indicators of what might be going on in your body, but there are a lot of different things that mucus colors can mean. So it’s always a good idea to talk to your doctor, especially if you’re also having bothersome symptoms.

Below, we talk about:

Mucus is good for the body (even if it’s kind of gross)

What is mucus? It’s a substance your body produces to help you stay healthy. It’s mostly water mixed with long molecules (called mucins). When combined, they form a thick, slippery, gel-like substance.

The purpose of mucus is to make your body run smoothly and keep irritants and germs away from your tissues. It can prevent infections and help you get better when you are sick.

Mucus does this by trapping germs, irritants and allergens before they get into your system. And if these invaders do get into your system, your body makes more mucus as a way to flush them back out. Your mucus may also become thicker so it’s better able to trap the nasty stuff before it makes you feel worse.

But thick mucus doesn’t always mean you’re sick – your body may also make thick mucus if you’re dehydrated as a way to protect your cells from damage.

Still, your mucus can only do so much. While it can usually help you get rid of viruses, it’s not so good at defeating bacteria. And mucus is pretty powerless against most medical conditions that can cause changes in the color and amount of mucus you have.

Mucus throughout your body: Some types have different names

Your body makes different types of mucus, and some types have their own names. Here’s what you should know about mucus throughout your body.

Snot is mucus in your nose

Healthy snot is thin mucus that’s watery. You’re constantly swallowing snot, even if you don’t realize it. Boogers are dried mucus that include debris or germs.

Snot is important because it keeps the linings of your nose and sinuses moist, making it easier to breathe. Your snot also filters the materials that you breathe in through your nose, including dust, allergens and germs that can cause a cold or the flu.

There are two ways that your snot changes to help you fight off infection. One way is that your body produces a lot more snot to help flush the gunk from your body as quickly as possible. Yes, that means your runny nose is a good thing.

The other possible change is thicker snot. Your nose may produce thick mucus if your nasal passages are inflamed because of a medical condition or illness such as a cold or allergies.

Thick mucus is better than thin mucus at trapping germs and substances. This means that the germs, irritants and allergens are less likely to get into your tissues – and more likely to come out when you blow your nose. It’s also common for snot to collect or dry out in your nose. This can cause hard nasal mucus or rubbery boogers.

Snot comes in a rainbow of colors – some of which can be signs that you should see a doctor. (We’ll get to that in a little bit.)

Phlegm helps clear your chest and lungs

So what is phlegm? It’s the mucus in your chest and lungs. Once phlegm is coughed up and out of your mouth, it’s called sputum.

Phlegm collects the particles and debris that you breathe in. One of the interesting things about chest mucus is that it has three layers. The bottom layer includes hair-like structures (cilia) that push the phlegm out of the airway and into the throat. When the phlegm gets to the throat, it’s usually swallowed and digested. But sometimes, you may cough up phlegm.

A phlegmy cough can happen when a lot of mucus collects in your chest. A phlegm buildup is usually from a medical condition or medication that causes thicker mucus that’s more difficult for the cilia to move. If your body isn’t able to clean your lungs of the phlegm, you may end up with a chronic cough.

If you have a lot of mucus in your throat and lungs, it can collect together, forming hard phlegm chunks. It’s normal to have balls or chunks of clear or white phlegm, even when you’re not sick.

Infections, medical conditions and airborne irritants can cause phlegm to change color. Often, phlegm changes are cause for a doctor visit.

Mucus in your gut helps with digestion

Your entire digestive system is lined with mucus. This mucus helps food, liquids and stool easily pass through your gut. Mucus also protects your cells by trapping bacteria and viruses that get into your digestive system.

It’s normal for a small amount of mucus to stick to your stool as it leaves your body. Mucus in stool can be hard to spot because it’s a clear or yellowish-brown color in your poop. If you’re starting to see a lot more mucus, that can be a concern.

Mucus helps clean your urinary tract

The mucus that lines your urinary tract helps protect your body and flush out germs that could cause infection. Mucus in urine is normal, but you usually don’t see it. When you should see a doctor about mucus in your urine depends on your anatomy:

  • People with female anatomy – Often see small amounts of clear, white or off-white mucus in their urine, and it’s usually not a problem. But if there’s a lot of mucus or if it’s a different color, you should see a doctor.
  • People with male anatomy – Noticeable mucus of any color in your urine can be a sign you should see a doctor.

What mucus colors mean: They can be a sign of sickness or health

The color of mucus comes from how it adapts to protect you and can signal illness or medical conditions. Then again, mucus colors can also change because of what you breathe, eat or drink.

Different mucus colors can be more concerning based on the source of the mucus. For example, snot captures stuff in the air, so it’s often no big deal if you have boogers that are gray, black or brown – but seeing those colors in phlegm or other mucus is usually a reason to head to the doctor.

Clear mucus is usually normal

Clear mucus is usually normal and healthy – but it’s possible to have too much of it. Having a lot of thin mucus is a sign that there’s something in your body that’s causing irritation or inflammation.

It’s possible for excessive clear mucus to go away on its own. But if you continue to have a lot, it’s a good idea to talk to your doctor about it.

Causes of excessive clear mucus

  • Clear snot – A very runny nose and a lot of clear phlegm are ways that your body tries to expel dust, pollenand other irritating particles.
  • Clear phlegm – Allergies and asthma are common causes of clear phlegm. Other reasons are viral bronchitis or viral pneumonia.
  • Clear mucus in stool – If you’re seeing a lot of mucus in your stool, it may mean your body started to make more digestive mucus because you have an intestinal infection, food allergies, cystic fibrosis or another medical condition.
  • Clear mucus in urine – You may have more clear mucus in your urine if you’re pregnant or if you have a hormone imbalance.

White mucus usually isn’t serious, but frothy phlegm can be concerning

White mucus is usually an early symptom of an illness. It can be a good sign, since it shows that your body is responding to viruses or bacteria in a normal, healthy way.

White snot usually isn’t anything to worry about. But white phlegm can be concerning, especially if it’s frothy or foamy. Depending on your other symptoms, white mucus in your urine may be a concern.

Causes of white mucus

  • White snot – Typically is one of the early signs of a viral infection, often the common cold. White snot generally isn’t associated with bacterial infections or other conditions that need medical treatment.
  • White phlegm – Can be a sign that you have a bacterial infection. If you have white phlegm that’s frothy or bubbly, it could mean that you have an illness or medical condition that should be treated. Possible reasons for frothy white phlegm include pneumonia, chronic obstructive pulmonary disease (COPD), gastroesophageal reflux disease (GERD), viral bronchitis and congestive heart failure.
  • White mucus in stool – Often nothing to worry about. But it can be a sign of an infection, food allergies or another medical condition. So it’s worth talking to a doctor if there’s a lot of it.
  • White mucus in urine – Can be normal, but if your urine is cloudy or if you have symptoms like pain when you pee, it’s possible you may have a urinary tract infection (UTI) or another medical condition, and you should see a doctor.

Yellow mucus usually means your body is fighting off an infection

Yellow mucus generally means that your body is fighting off a mild infection. The yellow color can come from dead white blood cells (infection-fighting cells) that are coming out in the mucus. You may also have yellow mucus when your body is getting rid of allergens.

Most of the time, you don’t need medical treatment for yellow snot or phlegm, but you should see a doctor if it sticks around for more than 10 days. Yellow mucus in your urine may need treatment sooner if it’s causing other symptoms.

Causes of yellow mucus

  • Yellow snot – Usually a viral, bacterial or fungal infection such as the flu, common cold or sinusitis. But it can also be caused by allergies.
  • Yellow phlegm – Typically a symptom of allergies or a viral, bacterial or fungal infection.
  • Yellow mucus in stool – Can be a sign that your body isn’t digesting fat normally or another digestive problem.
  • Yellow mucus in urine – May be a sign of a sexually transmitted infection (STI). If you’re experiencing pain when you pee or other symptoms, you should see a doctor.

Green mucus often follows yellow mucus

Green is another common mucus color if you have an infection – or when you’re recovering from one.

As you get over being sick, your mucus color will likely change from yellow to green. Chances are it will get thicker as well. The change in color and thickness is usually because your mucus now contains debris that’s mixed in with the dead white blood cells. But it’s also possible that your mucus is turning darker and thicker because you’re dehydrated.

If green mucus sticks around for a long time, it can also mean you have a bacterial infection (like a sinus infection) that needs to be treated with antibiotics. Talk to your doctor if your snot or phlegm stays green for 10 or more days – especially if you have a headache, fever or other bothersome symptoms.

Causes of green mucus

  • Green snot – Usually caused by an infection.
  • Green phlegm – Often caused by an infection. Can also be a sign of pneumonia, certain lung conditions and cystic fibrosis.
  • Green mucus in stool – If your poop is green, it’s probably not green mucus. But if there’s slimy or stringy green mucus in your baby’s poop, it can be a sign of infection, and you should see your baby’s doctor right away.
  • Green mucus in your urine – Can be a sign that you have an STI that should be treated.

Brown mucus can be from old blood or something in the air

Brown mucus usually contains old blood. But inhaling something that’s brown can also change the color of your mucus. Brown snot generally isn’t worth worrying about, but brown phlegm is worth a visit to the doctor.

Causes of brown mucus

  • Brown snot – Often means that you’ve breathed in dirt or something brown, but brown boogers can also mean that you have dried blood in your nose.
  • Brown phlegm – Usually caused by chronic lung inflammation from bronchitis, a lung disease or cystic fibrosis.

Pink or red mucus usually contains blood

If your mucus is pink or red, it means that there’s blood in your mucus. Bloody snot is usually cause by irritation of the nasal passages, and normally isn’t a big deal. But, coughing up red phlegm or seeing bloody mucus in the toilet is something you should talk to your doctor about.

Causes of pink or red mucus

  • Red snot – Many things can cause bloody snot, including dry weather, being sick, asthma or allergies, and picking or blowing your nose.
  • Red phlegm – Bloody phlegm can be a sign that you’re getting over being sick, but it can also be a sign of more serious infections and lung disease.
  • Red mucus in your urine – Bloody mucus in your urine is usually a sign of irritation and inflammation in the urinary tract because of an infection or a medical condition.
  • Red mucus in stool – Bloody mucus in your poop can be caused by hemorrhoids, digestive problems and medical conditions.

Black mucus can be a sign of something serious

Black mucus usually gets its color from airborne irritants or because your blood has mixed with bacteria, fungi or old cells.

Gray or black snot is usually nothing to worry about. But you’ll want to talk to your doctor if you’ve had black phlegm for more than a couple days, or have noticed gray mucus in your urine.

Causes of black or gray mucus

  • Black or gray snot – Breathable irritants like pollutants, fire and tobacco smoke can collect in your nose, changing the color of your mucus. Usually, these changes are temporary. Gray snot that doesn’t go away can be a sign of a fungal infection – see a doctor if you have a fever.
  • Gray or black phlegm – Airborne irritants can cause gray or black phlegm. Some things you breathe can do lasting damage, and even change how your lungs work. For example, cigarette smoke destroys the cilia that moves mucus out of your lungs. As a result, black phlegm gets stuck in your airways. Black phlegm can also be a symptom of lung cancer and bacterial infections like tuberculosis (TB) and pneumonia.
  • Gray mucus in urine – Can be a sign of bacterial vaginosis, a condition that’s caused by an overgrowth of normal vaginal flora.

How to get rid of mucus? The treatment depends on the cause

There are many different causes of excessive mucus. You may have a good idea of what’s causing changes in your mucus. But if you’re not sure, make an appointment with your primary care doctor.

How to get rid of mucus in your airway

Mucus in your nose, throat and lungs can often be treated at home. Here are some home treatments for managing mucus:

  • Breathe in warm, wet air – Breathing moist, warm air is one of the best ways to treat a cold and viruses. Taking a shower, soaking in the tub or turning on a humidifier can moisturize your throat and nasal passages, and loosen thick mucus.
  • Hydrate – Drinking more fluids can help you get rid of mucus in your throat and lungs. Warm, noncaffeinated beverages are usually best. Try to limit coffee and alcohol, which can be dehydrating.
  • Use a saline nasal spray – If you have thick or hard nasal mucus, a sterile spray with sodium chloride can be a great way to soften things up so you can blow the boogers out.
  • Keep your head elevated when you sleep – If mucus in your nose and throat are making it hard to sleep, try changing your sleeping position. Sometimes all you need is an extra pillow under your head for less mucus (and better sleep).
  • Eucalyptus – Eucalyptus products can help reduce the amount of phlegm you’re making. There are balms you can apply directly to your chest and essential oils that you can add to a diffuser or a warm bath.
  • Cold medications – Over-the-counter decongestants can help thin out thick nasal mucus, but they aren’t effective against phlegm. If you have a chest full of mucus, a better choice is an expectorant like guaifenesin (Mucinex) or horehound.
  • Allergy medications – If you think your runny nose is from allergies, there are over-the-counter medications you can try. It’s best to get recommendations from your doctor, but if you can’t wait, start with an oral antihistamine tablet. Zyrtec, Claritin and Benadryl are common options.
  • Make sure the air is clean – If you have excess mucus due to allergies, changing the filters on your heating and cooling systems can help treat allergy symptoms.
  • Breathing exercises – Doing upper body stretches can help clear mucus from your lungs and throat.

How to get rid of mucus in urine

To get rid of mucus in your urine, you’ll need a doctor’s help. It can be normal to have some mucus in your urine, but it can also be a sign of infection and other medical conditions. If you have pain while urinating or feel like you need to go all the time, you’ll want to talk to a doctor. A convenient way to get treatment for these types of conditions is to start an online Virtuwell visit.

How to get rid of mucus in stool

Having an excessive amount of mucus in your stool is often related to digestive problems. It’s possible that avoiding gluten or eating a colon-healthy diet could help, but it’s best to talk to your doctor before making changes. They’ll help determine the likely cause and what, if anything, you need to do. If it makes sense, they’ll refer you to a digestive health specialist.

Get clear advice for your mucus concerns

Your primary care doctor is your best resource to help you understand why your mucus has changed colors – or why you suddenly seem to have so much of it. Plus, they can tell you about the best treatments to get rid of mucus in your throat, lungs, nose and anywhere else. In particular, it’s a good idea to talk to your doctor about your mucus if:

  • Your symptoms are getting worse
  • You don’t get better within 10 days
  • You have a fever
  • You’re in pain
  • It’s difficult to breathe