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What Causes Brown, Black, or Colored Mucus With Your Cough

An illustration of a yellow side profile head facing right. The eye is scrunched and the mouth is open, three lines of three dots each come from the mouth. The top line is brown, the middle black, and the bottom yellow, light blue, and medium blue.
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Written by Jack Wilkinson, MD.
Fellow, Cornell/Columbia New York Presbyterian Child Psychiatry Program
Last updated April 15, 2024

Dark mucus cough quiz

Take a quiz to find out what's causing your dark mucus cough.

Coughing up black or brown mucus can occur when from environmental conditions like pollution or smoking. Other causes of brown phlegm include small amounts of blood located in the throat or further down in the airway. Read below for more information on causes and how to treat coughing up brown or black mucus.

Dark mucus cough quiz

Take a quiz to find out what's causing your dark mucus cough.

Take dark mucus cough quiz

Symptoms of black or brown expelled mucus

Coughing is a bothersome symptom that can be uncomfortable, annoying, and contagious. Chronic or severe coughing can make it difficult to catch your breath and can become painful over time.

Sometimes coughs are dry, but in many cases, they can produce mucus in different colors and consistencies, including white, green, brown, and black. The color may be a clue to the underlying cause of the cough.

Brown and black mucus may be accompanied by the following symptoms

It's likely to also experience:

What causes brown-black mucus?

Coughing is a sign of irritation to the respiratory tract, which includes your throat, windpipe or trachea, and lungs. Coughing helps the body to clear irritants. Mucus is produced to clean, protect, and moisten the respiratory tract. Though it can be unsightly, mucus fights infection and clear irritants. In most cases, brown or black mucus is caused by irritation from chemicals or pollution, or by small amounts of blood coming from your irritated airway.

Irritant causes

The following are common irritants that may cause coughing up brown or black mucus.

  • Smoking: Cigarette or cigar smoke is extremely irritating to your airways. Not only does it increase your risk of developing mouth, throat, and lung cancer, it also deposits tar and other irritants in your lung. Smoking may give mucus a brown or black color.
  • Pollution: When traveling to or living in cities with high levels of pollution, smog can deposit in your nose, mouth, and airways. It often appears brown or black when coughed up.
  • Coal mining: Classically called "black lung," this condition occurs in coal miners who inhale dust during their work if they do not wear appropriate protective equipment.
  • Fire: Inhaling smoke while around a fire can burn your airways and also deposit brown or black soot.

Infectious causes

Infections may lead to coughing up brown or black mucus, such as the following.

  • Tuberculosis: This serious lung infection is highly contagious and can be fatal if not properly treated. It is caused by bacteria that lie dormant in your body for many years until awakened when your immune system becomes weakened.
  • Fungus: It is unusual to have a fungal infection of your lungs and airways, though some are endemic — or regularly found in certain areas such as the Arizona and California desert regions. This infection can be extremely irritating, leading to inflammation and even bleeding that may appear as a brown tint in mucus.
  • Pneumonia: Pulmonary infections such as pneumonia can cause small amounts of bleeding in the lungs and airways.

Other causes

Other causes that may contribute to this symptom include the following.

  • Autoimmune: Certain conditions cause your body to attack its own respiratory system, leading to inflammation and bleeding.
  • Blood thinners: Drugs that your doctor prescribes may increase the risk for bleeding if you have a lung infection or are coughing for some other reason.
  • Heart valve problem: The heart and lungs are closely connected. If blood cannot flow properly through the heart, it can back up fluid, or edema, into the lungs. This fluid may present as bloodstained, brownish mucus with a cough.

9 coughing up brown-black mucus conditions

This list does not constitute medical advice and may not accurately represent what you have.

Viral pneumonia

Viral pneumonia, also called "viral walking pneumonia," is an infection of the lung tissue with influenza ("flu") or other viruses.

These viruses spread through the air when an infected person coughs or sneezes.

Those with weakened immune systems are most susceptible, such as young children, the elderly, and anyone receiving chemotherapy or organ transplant medications.

Symptoms may be mild at first. Most common are cough showing mucus or blood; high fever with shaking chills; shortness of breath; headache; fatigue; and sharp chest pain on deep breathing or coughing.

Medical care is needed right away. If not treated, viral pneumonia can lead to respiratory and organ failure.

Diagnosis is made through chest x-ray. A blood draw or nasal swab may be done for further testing.

Antibiotics do not work against viruses and will not help viral pneumonia. Treatment involves antiviral drugs, corticosteroids, oxygen, pain/fever reducers such as ibuprofen, and fluids. IV (intravenous) fluids may be needed to prevent dehydration.

Prevention consists of flu shots as well as frequent and thorough handwashing.

Rarity: Uncommon

Top Symptoms: fatigue, headache, cough, shortness of breath, loss of appetite

Urgency: Primary care doctor

Smoking-induced cough

The airways are lined with tiny cells called cilia, whose function is to catch toxins in air that is inhaled and push them up towards the mouth. When smoke is inhaled, the cilia are paralyzed for a short while, so toxins are allowed to enter the lungs and create inflammation. During the night, the cilia repair themselves and begin to push up all the accumulated mucus and toxins, causing an increase in cough in the morning.

You can treat this condition by quitting smoking.

Rarity: Common

Top Symptoms: cough

Symptoms that always occur with smoking-induced cough: cough

Symptoms that never occur with smoking-induced cough: fever

Urgency: Self-treatment

Lung abscess

An abscess is a collection of pus which results from an infection. A lung abscess may form following an infection such as pneumonia.

You should visit your primary care physician within the next 24 hours. Your doctor will confirm the diagnosis with an X-Ray. Treatment for a lung abscess involves prescription antibiotics.

Common cold

The common cold is a contagious viral infection that can cause cough, congestion, runny nose, and sore throat. Most adults catch two to three colds per year, and kids can get more than eight colds each year.

Rest and drink plenty of fluids. Colds are contagious and can easily spread to other people, so if possible, avoid close contact with others, such as hugging, kissing, or shaking hands. Colds typically resolve within 7 to 10 days.


Bronchitis is an inflammation of the bronchial tubes, the tiny airways in the lungs.

Acute bronchitis, or "chest cold," comes on suddenly and is caused by the same virus that causes the flu or the common cold. Chronic lasts at least three months and recurs over two years. It is caused by cigarette smoking and/or exposure to other pollutants.

Other risk factors are weakened immune system and gastric reflux (heartburn.)

Symptoms include cough with clear, greenish, or yellowish mucus; fatigue; mild headache; body aches; shortness of breath; low-grade fever; chest discomfort.

Acute bronchitis can lead to pneumonia. Chronic bronchitis is a form of chronic obstructive pulmonary disease (COPD) and requires medical treatment.

Diagnosis is made with chest x-ray and sputum test.

Acute bronchitis lasts 7 to 10 days and needs good supportive care – rest, fluids, and over-the-counter pain relievers. Antibiotics do not work against viral illness.

Chronic bronchitis is treated with lifestyle changes – especially smoking cessation – and an inhaler or other lung medication.

Flu shots, frequent handwashing, and not smoking are the best prevention.


Bronchiectasis is destruction and widening of the large airways. Mucus builds up in these airways and can get infected, causing a pneumonia.

You should visit your primary care physician within the next 24 hours if you might have an infection. Diagnosis involves a chest X-ray, sampling phlegm, blood tests, and other possible tests. Treatment is mostly coaching, actually, on exercises that strengthen your ability to cough up phlegm.

Rarity: Rare

Top Symptoms: cough, shortness of breath, wheezing, runny nose, mucous dripping in the back of the throat

Urgency: Primary care doctor

Bacterial pneumonia

Bacterial pneumonia is an infection of the lungs caused by one of several different bacteria, often Streptococcus pneumoniae. Pneumonia is often contracted in hospitals or nursing homes.

Symptoms include fatigue, fever, chills, painful and difficult breathing, and cough that brings up mucus. Elderly patients may have low body temperature and confusion.

Pneumonia can be a medical emergency for very young children or those over age 65, as well as anyone with a weakened immune system or a chronic heart or lung condition.

Complications may include organ failure and respiratory failure. Take the patient to the emergency room or call 9-1-1.

Diagnosis is made through blood tests and chest x-ray.

With bacterial pneumonia, the treatment is antibiotics. Be sure to finish all the medication, even if you start to feel better. Hospitalization may be necessary for higher-risk cases.

Some types of bacterial pneumonia can be prevented through vaccination. Flu shots help, too, by preventing another illness from taking hold. Keep the immune system healthy through good diet and sleep habits, not smoking, and frequent handwashing.

Rarity: Common

Top Symptoms: fatigue, cough, headache, loss of appetite, shortness of breath

Symptoms that always occur with bacterial pneumonia: cough

Urgency: In-person visit

Acute viral sinusitis

Acute viral sinusitis, also called viral rhinosinusitis or "sinus infection," occurs when viruses take hold and multiply in the sinus cavities of the face.

It is most often caused by the same viruses that cause the common cold and spreads the same way, through an infected person's coughing or sneezing.

Because children have small, underdeveloped sinuses, this illness is far more common in adults.

Symptoms include clear nasal discharge (not greenish or yellowish,) fever, and pain if facial sinuses are pressed.

If there is rash, severe fatigue, or neurologic symptoms (seizures, loss of sensation, weakness, or partial paralysis,) see a medical provider to rule out more serious conditions.

Diagnosis can usually be made through history and examination alone.

Antibiotics only work against bacteria and cannot help against a viral illness.

Therefore, treatment consists of rest, fluids, and fever/pain reducers such as ibuprofen. (Do not give aspirin to children.) Symptoms of viral sinusitis last for about seven to ten days.

As with the common cold, the best prevention is frequent and thorough handwashing.

Rarity: Common

Top Symptoms: headache, cough, sinusitis symptoms, sore throat, congestion

Symptoms that always occur with acute viral sinusitis: sinusitis symptoms

Symptoms that never occur with acute viral sinusitis: being severely ill

Urgency: Self-treatment

Ways to prevent and treat brown-black mucus

Nearly all causes of coughing up brown or black mucus require a visit to the doctor's office for further evaluation. Testing will determine the underlying cause of your problem, and you can work with your doctor to determine the best treatment plan. In the meantime, there are some steps you can take at home to address the situation as well.

At-home treatments

You can try the following remedies at home for potential relief.

  • Stop smoking: If you smoke, there are many reasons to stop. Brown or black mucus is another sign that smoking is harming your body. Keep in mind that it also harms those around you through second-hand smoke.
  • Avoid irritants: If you live in a polluted city, wear a mask and limit your time outside. If your work exposes you to irritants, wear appropriate protective equipment.
  • Cover your mouth: If you have signs of an infection like fever, weight loss, muscle aches, or night sweats, cover your mouth when you cough and stay away from others to avoid spreading the infection.

Here are some over the counter treatment that might help:

  • Expectorants: Medications like guaifenesin can help loosen the mucus and make it easier to cough up. This can be particularly helpful if your mucus is thick and difficult to expel.
  • Cough Suppressants: If your cough is dry and painful, using a cough suppressant may provide relief. However, if you're producing mucus, it's best to avoid suppressing your cough too much as it helps clear the irritants from your lungs.
  • Nasal Decongestants: If you're also experiencing congestion, a nasal decongestant can help reduce the mucus production and ease breathing.

When to see a doctor

If you continue to cough up brown or black mucus, or it becomes worse, you should see a doctor. He or she may recommend or complete the following.

  • Detailed history: Your doctor may ask about your work, travel, recent contacts, smoking habits, and other topics.
  • Prescription medications: Antibiotics are appropriate if your doctor suspects an infection. Other drugs can treat inflammation from autoimmune diseases and other problems.
  • Imaging: A chest X-ray is the first line of testing for most people with a cough. Other studies, like CT scans, may also be ordered and offer a more detailed look at your lungs and airways.
  • Bronchoscopy: In this procedure, a lung doctor inserts a tube, or scope, with a small camera into your airways and lungs to look for the cause of your cough and mucus production. A biopsy may be taken if a suspicious area is noted.

When it is an emergency

Seek help without delay if you experience the following.

  • Worsening difficulty breathing
  • Cough producing blood
  • Significant weight loss
  • History of cancer or autoimmune disease
  • Exposure to tuberculosis

Questions your doctor may ask about coughing up brown-black mucus

  • Any fever today or during the last week?
  • Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
  • Do you currently smoke?
  • Do you have a sore throat?

Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.

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The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.
Dr. Rothschild has been a faculty member at Brigham and Women’s Hospital where he is an Associate Professor of Medicine at Harvard Medical School. He currently practices as a hospitalist at Newton Wellesley Hospital. In 1978, Dr. Rothschild received his MD at the Medical College of Wisconsin and trained in internal medicine followed by a fellowship in critical care medicine. He also received an MP...
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