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09/24/2024 | Press release | Distributed by Public on 09/24/2024 13:45

Health Myth Debunked: Green Mucus Means You Have an Infection — or Does It

Key takeaways:

  • Mucus plays an important role in the body. It acts like a moisturizer for tissues in your body and works with your immune system to protect you from illness.

  • The color and consistency of mucus can vary a lot. But these changes aren't a reliable way to tell the difference between a bacterial or viral infection - or if you even have an infection at all.

  • Many people think that green mucus means they have an infection. But mucus color alone isn't a reliable way to say for sure.

  • Paying attention to other symptoms, like fever or trouble breathing, can help you figure out what's going on.

Drazen Zigic/iStock + via Getty Images Plus
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  • When do you really need antibiotics? Antibiotics can help treat bacterial infections. But taking them when you don't need them can lead to problems down the road.

  • What can your cough tell you? Coughs are pretty much universally irritating and unwelcome. But there are many types of cough, and they can give you clues about your health.

  • Is it a cold or a sinus infection? Lots of things can prompt your body to make more mucus. Learn the differences between colds versus sinus infections.

You may have heard that green mucus, boogers, or snot mean you have an infection. But it turns out that the color of your mucus isn't a dependable way to figure out whether you have an infection. Lots of things can change the color and consistency of your mucus, like bacterial and viral infections and allergies.

And it's important to figure out what's causing your symptoms. That's because the cause informs the best treatment. For example, antibiotics are only designed to treat bacterial infections. Taking antibiotics for a viral illness can complicate your treatment and recovery.

Here's a closer look at what green mucus can and can't tell you.

Does green mucus mean infection?

No, green mucus doesn't necessarily mean that you have an infection. You may get green mucus with a viral or bacterial infection. Or your mucus may be green, even if you don't have an infection at all. On its own, the color of your mucus doesn't tell you a whole lot.

A change in the color, consistency, or amount of mucus may catch your attention. But, in reality, mucus is always present in your body. Mucus provides a sticky coating and contains helpful antibodies and enzymes, which help catch viruses and bacteria before they can infect you. Jayne Morgan, MD, creator of the Stairwell Chronicles and executive director of health and community education at Piedmont Healthcare, put it this way: "Think of mucus as a line of defense."

Mucus is also a natural part of the body's immune response when it's fighting off illness. But, if you've been experiencing nasal drainage for 7 days or more, or if you start to get better but then get worse again, that could be a sign of a bacterial infection, explained Zachary Willis, MD, MPH, a pediatric infectious diseases physician at University of North Carolina School of Medicine.

"Because yellow and green mucus tend to happen later in the infection, that's when people start to worry that their infection has been going on for too long," Dr. Willis said. And this appearance of colorful mucus can make people jump to the conclusion that they have a bacterial infection that needs an antibiotic. But that's a misguided assumption.

What does the science say about green mucus?

One study looked at green mucus samples from people with a cough and no other lung conditions. It found that only about 1 in 10 of those green mucus samples were caused by a bacterial infection. This means that most people with green mucus don't have a bacterial infection. In short, mucus color alone isn't a reliable way to say whether you need antibiotics.

So, what does a change in mucus color mean?

The lining of your nose, sinuses, and throat makes mucus to keep airways clean and moist. But lots of things can prompt your body to produce more mucus than usual, including:

This extra mucus can lead to postnasal drip. This is a feeling of mucus draining from the nose or sinuses into the throat. If you've coughed up this mucus or blown your nose, you've likely noticed that the colors can vary quite a bit.

Even if your mucus is caused by an infection, a change in color doesn't mean it's more serious. In general, yellow or green mucus is often a sign that the body is working hard to fend off infection. "These are white blood cells rushing to battle," said Dr. Morgan. "Then, they are flushed out."

It's also possible that cells involved in inflammation change the color of mucus from its usual clear color to yellow or green.

When to go to the doctor's office for green mucus

Green mucus alone isn't a cause for concern. As Dr. Morgan noted earlier, the color change likely means that your body is already successfully fighting off an infection.

So, if you feel OK, you can try to relieve an irritated throat or postnasal drip with some at-home remedies, like a humidifier or saline rinse.

But it's important to take into account other symptoms you may have. Dr. Morgan noted that something more serious may be going on if your mucus turns green and you also experience:

  • Fever

  • Shortness of breath

  • Chest pain

If you have an underlying lung condition, any change in your cough or mucus could be a sign that you're having a flare. If you notice green (or any color) mucus, talk to a healthcare professional as soon as possible.

Frequently asked questions

Do you need antibiotics for green mucus?
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No, you don't necessarily need antibiotics for green mucus. Most sinus infections are caused by viruses - not bacteria. And antibiotics won't help with viral infections.

In fact, taking too many antibiotics can lead to antibiotic resistance. This is when antibiotics no longer work against bacteria, making it more challenging to treat the infection.

A healthcare professional can help you figure out what's causing your symptoms.

Does yellow mucus mean you are getting better?
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Maybe - yellow mucus might mean you're getting better. But mucus color isn't a proven way to tell you the stage of an illness or the type of illness you may have. Whether your mucus is yellow, green, or clear, consider any other symptoms you're experiencing to get a better idea of how you're doing.

Am I contagious if I cough up green mucus?
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It's possible you've contagious if you cough up green mucus. But it's hard to say for sure since so many things can lead to a cough and green mucus.

Many respiratory infections, like the common cold and the flu, can spread when you cough. So, until you know what's causing your cough, it's a good idea to:

  • Limit contact with others.

  • Wear a mask in public spaces.

  • Cover your mouth with your elbow or tissue when you sneeze or cough.

  • Wash your hands often with soap and water.

The bottom line

Seeing green mucus may come as an unwelcome surprise. But it doesn't always mean that you have an infection. In fact, green mucus is a normal immune response. So, to get a better idea of what a change in your mucus color or consistency means, you'll need to take into account any other symptoms you may be experiencing. If it's been a few days and your symptoms are lingering or worsening, connect with a healthcare professional to figure out the cause.

Why trust our experts?

Written by:
Alex Eastman, PhD, RN
Alex Eastman, PhD, RN, is a California-based registered nurse and staff medical editor at GoodRx, where he focuses on clinical updates and Latino health.
Reviewed by:
Karen Hovav, MD, FAAP
Karen Hovav, MD, FAAP, has more than 15 years of experience as an attending pediatrician in a variety of clinical settings. She has worked in a large academic center in an urban city, a small community hospital, a private practice, and an urgent care clinic.

References

Altiner, A., et al. (2009). Sputum colour for diagnosis of a bacterial infection in patients with acute cough. Scandinavian Journal of Primary Health Care.

Brook, I. (2011). Microbiology of sinusitis. Proceedings of the American Thoracic Society.

View All References (3)
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News in Health. (2020). Marvels of mucus and phlegm: The slime that keeps you healthy. National Institutes of Health.

Scarupa, M. D., et al. (2009). Nonallergic rhinitis, with a focus on vasomotor rhinitis clinical importance, differential diagnosis, and effective treatment recommendations. World Allergy Organization Journal.

Zanin, M., et al. (2016). The interaction between respiratory pathogens and mucus. Cell Host & Microbe.

GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.

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