Brown Mucus/Phlegm Symptoms

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Mucus comes in a variety of colors (green, white, reddish-pink, or brown), textures, and even names (such as sputum and phlegm). Clear or watery phlegm is usually not worrisome. It is associated with benign conditions like seasonal allergies, post-nasal drip, or a cold.

Less commonly, you may find yourself coughing up brown mucus, which may be associated with a number of conditions, including smoking, chronic lung disease, or infections. 

The presence of tar, dirt, or old blood or the inflammation of the lower portions of the throat and upper airways are the most common reasons for brown phlegm. This article will explain the symptoms associated with brown mucus, its many causes, and how to treat it. 

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Symptoms of Brown Mucus/Phlegm

The presence of brown mucus may be worrisome, especially if you are a current or former smoker. The most common symptom associated with brown mucus or phlegm is a cough. A cough associated with any type of mucus is called a productive cough. Other symptoms associated with brown phlegm include:

  • Fever
  • Chills
  • Shortness of breath
  • Congestion
  • Sneezing or sniffles 
  • Wheezing
  • Chest pain, especially pain on inspiration (breathing in) or expiration (breathing out)
  • Sore throat
  • Sweating
  • Exercise intolerance
  • Fatigue
  • Unexplained weight loss 

Causes of Brown Mucus/Phlegm

If you notice you have brown phlegm, you don't need to be excessively alarmed, especially if you are young, generally healthy, and have no smoking history or other risk factors.

Still, you should never take the presence of brown phlegm lightly. Get checked by a healthcare provider to make sure that more serious underlying conditions are not the cause of your symptoms.

Brown phlegm can be caused by a wide range of conditions, including:

  • Smoker's cough: Tar from the lungs due to chronic smoking may be brought up with coughing.
  • Exposure to air pollution.
  • Inhalation of toxic environmental or occupational substances such as coal dust from mining (coal workers' pneumoconiosis).
  • Viral infection.
  • Chronic lung disease: Chronic lung diseases like chronic obstructive pulmonary disease, chronic bronchitis, bronchiectasis, and emphysema are often associated with long-term smoking, although genetic conditions like cystic fibrosis and interstitial lung disease may also cause brown mucus.
  • Lung cancer: Smoking is the major risk factor for lung cancer, but it can occur in non-smokers. Your risk of lung cancer remains high even 15 years after quitting smoking. Quitting early, before the age of 40, has also been associated with a lower lung cancer risk.
  • Bacterial pneumonia: Bacterial infections damage the tissues that line the lungs. Bleeding, especially old blood that remains in the lungs, can taint the mucus in your upper airways and make it appear brown.
  • Lung abscess: This is a pocket of infection in the lung, often caused by aspirating material into the lungs. Sometimes a productive cough is the first sign of a lung abscess.
  • Asthma (rarely).

How to Treat Brown Mucus/Phlegm

The presence of brown phlegm can be alarming, but if you are generally healthy and have no history of smoking, chances are you have a benign condition that can be treated.

The most definitive way to get rid of your brown phlegm is to resolve the underlying condition that is causing your symptom in the first place.

If the cause of your lung damage is primarily due to smoking, your healthcare provider will suggest that you quit immediately. You may notice that your symptoms are getting better in just a matter of days or weeks.

If air pollution or toxic substances are the cause of your lung damage, it may be best for you to move or quit your job, although understandably, this may not be feasible for everyone. Sometimes contaminants in the home (such as mold) can be mitigated if identified.

Antibiotics may be used to treat bacterial pneumonia and lung abscesses. Antivirals may be used in some types of viral infections. Finally, lung cancer is often treated with a combination of surgery, chemotherapy, and radiation.

Complications and Risk Factors Associated With Brown Mucus/Phlegm

Your mucus turns brown because damage to the upper respiratory tract from chronic inflammation mixes mucus with old blood, tar, or debris (or a combination of all three). Inflammation within the lung also leads to an overall increase in mucus production which can cause a chronic cough.

Medical complications associated with the development of brown mucus or phlegm include:

  • Lung cancer
  • Lung abscess
  • Bacterial pneumonia
  • Black lung (coal miners' lung or coal workers' pneumoconiosis)
  • Fungal infections of the lung, such as aspergillosis
  • Lung damage due to smoke inhalation from a house fire or wildfire

The following risk factors are associated with an increased risk of upper respiratory lung damage:

  • Older age
  • History of smoking (especially a history of early smoking before age 45 for 10 or more years)
  • Occupational exposure to chemicals toxic to the lungs
  • Weakened immune system

Are There Tests to Diagnose the Cause of Brown Mucus/Phlegm?

The tests for diagnosing the cause of your brown mucus will depend on your clinical presentation, medical/smoking history, and physical examination.

  • Labs: A complete blood cell count with differential, viral tests (flu and COVID-19), and a basic metabolic panel can help detect underlying infections. 
  • Imaging: A chest X-ray is a quick, cheap, and effective way to identify the presence of infection (pneumonia or abscess) in the lungs. Computed tomography (CT) scans of the lungs can provide a more detailed look at the damage, especially by tumors or chronic lung diseases. 
  • Bronchoscopy: A scope with a camera at the end can look at your lungs and even be used to biopsy (take a sample for analysis) suspicious lesions or masses that may be the cause of your brown phlegm.
  • Sputum culture: This test looks for organisms (fungi or bacteria) that may be causing an infection in the lungs.

When to See a Healthcare Provider

If your symptoms do not improve or worsen even after treatment or present with ominous signs such as thick or smelly discharge, fever, shortness of breath, extreme fatigue, or unexplained weight loss, seek immediate medical attention.

Consulting a healthcare provider may help you to determine new or better treatments or help you determine if there is a need for more imaging and a bronchoscopy to figure out the precise cause of your brown sputum. 


Brown mucus is a less common form of phlegm that is caused by a variety of conditions, ranging from smoking and air pollution to chronic lung disease and bacterial or viral infections. See a healthcare provider if this symptom persists or is accompanied by other symptoms such as fever, shortness of breath, chest pain, or unexplained weight loss.

A Word From Verywell

Mucus production is important to your health because it protects against infection. It serves the dual role of trapping debris and foreign substances while also keeping your airways moist. Under normal circumstances, mucus is clear and thin, but if it changes color, it may be a sign of underlying disease.

If your mucus has changed color, texture, or volume, worsened despite treatment, or is associated with systemic symptoms like fever or significant weight loss, seek immediate medical attention because this may be a sign of a medical emergency.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. The Ohio State University Wexner Medical Center. What does the color of phlegm mean?

  2. American Cancer Society. What causes lung cancer?

  3. Thomson B, Emberson J, Lacey B, et al. Association of smoking initiation and cessation across the life course and cancer mortality: prospective study of 410,000 US adultsJAMA Oncology. 2021;7(12):1901-1903. doi:10.1001/jamaoncol.2021.4949

  4. Kuhajda I, Zarogoulidis K, Tsirgogianni K, et al. Lung abscess-etiology, diagnostic and treatment options. Annals of Translational Medicine. 2015;3(13):183. doi:10.3978/j.issn.2305-5839.2015.07.08

  5. Kuhajda I, Zarogoulidis K, Tsirgogianni K, et al. Lung abscess-etiology, diagnostic and treatment options. Ann Transl Med. 2015;3(13):183. doi:10.3978/j.issn.2305-5839.2015.07.08

By Shamard Charles, MD, MPH
Shamard Charles, MD, MPH is a public health physician and journalist. He has held positions with major news networks like NBC reporting on health policy, public health initiatives, diversity in medicine, and new developments in health care research and medical treatments.