If you look at a tissue after blowing your nose, you might see a fluid that’s clear, green, yellow or another color—which colors are normal and healthy for phlegm and mucus?
And which colors should cause you concern?
In general, mucus color alone isn’t enough to prove that you have an illness or that you need an antibiotic or other treatment.
Still, when mucus increases or changes color, you may want to know what it typically means.
In this article, I’ll explore what you need to know about each color of mucus, what healthy phlegm should look like, and how to know when you should see a doctor.
Mucus Color Meaning
Many people assume that the color of your mucus can help diagnose whether you’re sick or not.
But many different mucus colors can be normal, and antibiotics or medications should not be prescribed on the basis of mucus color alone.
Phlegm from the sinus cavity can be clear, white, yellow, green and beyond.
While it’s most common to have very little mucus—or for the mucus to be clear—having mucus that is a color does not necessarily mean you are sick.
Many things can lead to changes in your mucus color, including:
- Seasonal allergies
- Environmental allergies
- Contact with substances from work or outdoor activities
- Irritation or injury
Mucus helps to moisturize and protect the lining of your nasal passages.
If they get irritated, more mucus may be produced.
Mucus also helps protect you from germs that you might breathe in.
It can’t always prevent infection, but it’s a first line of defense to clean air before it goes down into the lungs.
The following color guide may give you an idea of what’s going on with changes to phlegm, but the only way to really know is to see a healthcare provider if you notice sudden changes in mucus volume or color.
If your phlegm turns yellow or yellowish-green, this is most commonly associated with an infection, like the common cold.
Mucus turns yellow as immune cells increase their numbers in your phlegm.
These include white blood cells that are destroying germs; they are discarded in the mucus when they’re done.
If your symptoms are not improving at all after 10-14 days, are worsening after a week, or if you are feeling very unwell, check in with your healthcare provider.
When mucus turns green, it is usually after it has already been yellow.
This may be a sign that your immune system is fighting an infection even more.
Since snot color alone can’t tell you or your medical provider whether your sickness comes from a virus or bacteria, green snot does not automatically mean that you will need antibiotics.
If you have yellow or green snot for more than 10-14 days, or it comes with other signs of sickness that aren’t resolving or are worsening after 7 days, check in with your healthcare provider.
They can determine if you do need an antibiotic or other medication to help your body get past the infection.
Brown or orange
It might feel alarming to see brown or orange-tinged mucus, but in many cases, this is a sign of old blood.
This can happen if you have allergies, a cold, are exposed to dry or cold air and blow your nose a lot, or if you are prone to getting bloody noses.
It is also possible that your mucus color appears brown or orange because you accidentally breathed in something that was this color, like dirt or a cooking spice.
In rare cases, certain lung disorders or infections can lead to changes in phlegm color from bleeding or inflammation.
These can include:
- Chronic lung disease
- Cystic fibrosis
If you notice persistent brown or orange phlegm, see a doctor or healthcare professional.
White phlegm can be caused by excessive mucus production from allergies or asthma, but it can also be caused by viral illnesses.
White mucus from an infection is most likely to be associated with a common viral infection, like a cold.
Since more than 1 billion cold infections happen every year, this is a pretty likely cause.
If you take antihistamines or medication to manage asthma, this may help alleviate white mucus.
If it’s from an illness and does not resolve within 10-14 days, worsens after 7 days, or you feel very unwell, check in with your healthcare provider.
In some cases, chronic lung problems that are not well-controlled can lead to white mucus.
These can include asthma, COPD, or other disorders.
Pink, red or brown
Seeing pink, red, or brown phlegm is usually a sign of bleeding somewhere in your nasal cavity or respiratory tract.
This is a reason to call your doctor or healthcare provider, unless you know that it’s caused by a short-term bloody nose that has already resolved.
If you get frequent bloody noses, check in with your healthcare provider.
If you are pregnant, you may experience more frequent bloody noses.
This happens because blood volume increases in pregnancy, hormone changes can impact mucus production, and nasal passages may swell.
In rare, but serious cases, pink, red, or brown mucus that isn’t just a one-time occurrence could be associated with a lung infection or cancer.
Black snot might feel alarming, but if you smoke or live in a household with someone who smokes, black, gray, or charcoal-colored snot can be common.
Blackish mucus can also happen if you live in an area where you regularly breathe in a lot of air pollution, or if you have recently been around a campfire.
Black snot can also be caused from using illegal drugs.
In rare cases, black mucus may be a sign of a serious fungal infection in the sinus cavity.
These are more likely to happen in people who already have compromised immune systems.
If you notice black mucus, see a healthcare provider as soon as possible for a diagnosis and treatment.
Other color meanings
Clear phlegm is considered to be normal.
A sudden increase in the volume of clear snot can indicate irritation from allergies, which is sometimes called hay fever.
When your body produces a lot of clear mucus, it may also come with symptoms like:
Pregnant people may also develop a condition known as nonallergic rhinitis, where they experience allergy-related symptoms with increased mucus, but the cause is hormone changes.
This most commonly occurs in the second trimester.
What is the Color of Healthy Mucus?
Healthy mucus should be clear and relatively unnoticeable.
Mucus serves to lubricate the lining of your nasal passages.
It also protects against germs or pathogens that you breathe in.
For the most part, you should be unaware of your mucus.
Mucus color and health correlation
If mucus changes color or increases in volume, there’s a reason for it.
For many people, a lot more clear snot typically means that it’s allergy season, or that you’ve been exposed to an environmental trigger like pet dander or mold.
When mucus changes color, it usually indicates that something is going on.
But in most cases, a healthcare provider won’t be able to diagnose the cause of mucus changes just from the color alone, and will determine the right treatment based on your overall health and specific symptoms.
They may recommend that you try an antihistamine, decongestant, or over-the-counter pain reliever to address your symptoms.
If mucus production remains high for more than two weeks, or worsens after a week and you have other signs of illness (like fever, cough, or chills), your healthcare provider may consider bacterial infection.
If you do have a bacterial infection, antibiotics could provide relief.
But they won’t be effective if your mucus production is caused by a virus or from allergies.
When to See a Doctor or Healthcare Provider
If your mucus is clear, but you’re producing a lot, a healthcare provider may be able to prescribe or recommend an antihistamine or other medication to help provide symptom relief.
If you have not been diagnosed with seasonal allergies, speak with a healthcare provider if mucus production suddenly increases and does not resolve within 5-10 days or does not improve with over-the-counter medications—even if you don’t feel unwell.
In rare cases, if you seem to be leaking thin, clear fluid from the nose that is not accompanied by other typical signs of allergy, it could indicate a leak for cerebrospinal fluid (CSF).
This is not common, but could happen after a severe injury or surgery.
Signs of a CSF leak include:
- Clear, watery-like fluid that leaks from the nose
- Severe headache
- Light sensitivity
- Neck pain
- Vomiting and nausea
- Irritability and agitation
- Feeling better if you lie down and worse if you stand up
If you think you are experiencing signs of a CSF leak, seek immediate emergency medical attention.
How K Health Can Help
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Frequently Asked Questions
K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.
Physiology, nasal. (2021).
The interaction between respiratory pathogens and mucus. (2017).
Sputum color for diagnosis of a bacterial infection in patients with acute cough. (2009).
Common cold. (2021).
Mucus, Mucins and Cystic Fibrosis. (2020).
Rhinitis as a cause of respiratory disorders during pregnancy. (2013).