Phlegm Colors Explained: Causes & When to Be Concerned

Key takeaways:

• Discolored phlegm does not always indicate the need for an antibiotic.
• Some colors of phlegm should be treated more seriously than others.
• Regardless of the color, if you are experiencing significant shortness of breath or chest pain, you should be seen by a doctor.

Phlegm is essential in protecting your respiratory tract. Its primary purpose is trapping and removing harmful particles like dust, allergens, and pathogens from the lungs. Phlegm is usually clear and thin, but the color can change when you are sick or when your body responds to an irritant.

The color of your phlegm doesn’t always provide helpful information, but when paired with other information, it can give us clues about the underlying cause. In this article, we will review the different colors of phlegm, their potential causes, and what they might indicate about your respiratory health.

Why phlegm colors change and what it means for your health

Phlegm color changes are often linked to various factors, ranging from harmless viral infections to more serious bacterial infections or chronic lung conditions.

Different phlegm colors explained

Phlegm comes in many different colors, and each can have distinct meanings. Below, we will review what the various colors are saying about your lungs.

White phlegm

White phlegm is usually the result of inflammation in the lungs. Inflammation can be due to acute infections, chronic lung conditions, allergies, or irritation from inhaled pollutants or chemicals. Unless you are coughing up copious amounts of white phlegm over extended periods, this is typically not a cause for concern.

Clear phlegm

Generally speaking, clear phlegm is considered normal and does not need evaluation or intervention from a doctor. If you are coughing up a significant amount of clear phlegm, this may be a sign of underlying lung disease and should be evaluated.

Yellow phlegm

Yellow phlegm can signify your body is fighting a bacterial or viral infection. The yellow color typically comes from white blood cells that are fighting the pathogen in your airways. If you are coughing up yellow phlegm and have other signs of an infection, such as a fever, you should see your doctor. Yellow phlegm is also common in patients with cystic fibrosis, which is a chronic condition.

Orange phlegm

Orange phlegm is often a sign that some amount of blood mixed with the mucus. This could be caused by irritation in the airways or nasal passages due to allergies, smoking, or an acute infection. If you notice orange phlegm, you should speak with your doctor. In addition to infection, this can also be a sign of a lung tumor or lung disease.

Pink or red phlegm

Pink phlegm can be a sign of pulmonary edema, which is fluid in the lungs. You should be especially suspicious of pulmonary edema if you are coughing up pink, frothy sputum. Pulmonary edema is common in people with congestive heart failure and should be treated as a medical emergency. Red phlegm is likely due to blood, which may result from an acute infection, a blood clot, a chronic condition, or lung cancer.

Brown phlegm

Brown phlegm typically indicates old or dried blood from somewhere within the respiratory tract. This is common with chronic lung conditions such as COPD, but may also be seen with acute lung infections. Smokers can cough up brown phlegm because the chemicals in the cigarettes and the cigarette smoke itself can discolor the phlegm. Inhaling pollutants or chemicals trapped in the phlegm can also cause it to turn brown.

Black phlegm

Black phlegm is most commonly associated with exposure to inhaled toxins, such as smoke, pollution, or dust. Occupational hazards such as coal dust or asbestos exposure may also produce black mucus due to a condition known as pneumoconiosis. Pneumoconiosis is more likely to occur with prolonged periods of exposure. If your phlegm has black specks in it, you should consider a fungal infection known as aspergillosis as the possible cause.

Causes of phlegm color changes

Phlegm color changes can be influenced by various factors ranging from infections to lifestyle habits to workplace exposures. Below are some of the most common causes of phlegm color changes.

Respiratory infection

As we briefly covered above, respiratory infections are one of the most common causes of phlegm color changes, particularly when you are coughing up yellow or green phlegm. When something foreign enters your respiratory tract, including an infectious pathogen, white blood cells rush to the area to try and clear the lungs, and as the white blood cells die, this can cause a yellow to green discoloration of the phlegm.

More intense green colors are noticed with bacterial infections. Fungal infections can also cause a change in phlegm color, although fungal infections are usually associated with black specks in the phlegm.

Chronic conditions

Different types of chronic conditions can be responsible for different phlegm colors. If you have a heart condition known as congestive heart failure, you are at a higher risk of pulmonary edema, which can lead to pink, frothy phlegm.

COPD, emphysema, and bronchitis may cause bleeding in the respiratory tract due to chronic inflammation and can lead to brown or red-colored phlegm. Cystic fibrosis is associated with producing a copious amount of yellow phlegm.

Smoking

Cigarette smoke can lead to brown and black discoloration of the phlegm due to chronic inhalation of smoke, tar, and chemicals. Smoking can also lead to chronic conditions such as COPD or even lung cancer that can cause bleeding in the lungs and respiratory tract and subsequent discoloration of the phlegm.

Environmental factors

Environmental factors, including dry climate, areas of high air pollution, and workplace hazards such as exposure to coal dust and asbestos, can all impact the color of phlegm. Inhaling pollutants and chemicals, particularly over a long period can lead to brown and black phlegm. Dry climates can lead to dry, irritated airways and the potential for bleeding of superficial vessels.

When you should see a doctor about a change in your phlegm’s color

If you notice that your phlegm has changed color, assessing any additional factors can help you determine if medical attention is needed.

You should see a doctor if:

• Your phlegm has been discolored for more than a week.
• You experience additional symptoms indicating an infection, such as a fever.
• You notice a small amount of blood in your phlegm.

You should go to the emergency room if:

• You are coughing up large amounts of blood.
• You are experiencing significant shortness of breath or chest pain.
• Your phlegm is pink and frothy, indicating fluid in the lungs.

Questions to ask your doctor about a change in your phlegms’ color

• What could be causing my phlegm to change color?
• Is this a sign of lung cancer?
• If my phlegm is anything other than clear, do I need an antibiotic?
• Do I need any diagnostic tests, such as a chest X-ray?

How a doctor can help managing changing or alarming phlegm colors

In some cases, discolored phlegm will resolve on its own with supportive care. Other times, your doctor may make recommendations to treat the symptoms.

Antibiotics

If the cause of your discolored phlegm is a bacterial infection like pneumonia, your doctor may prescribe antibiotics to help fight the infection. Antibiotics are not effective in treating viral infections.

Manage underlying conditions

If you have a chronic condition such as COPD (including emphysema or chronic bronchitis), your doctor may prescribe maintenance medications like inhaled corticosteroids. Other medications will be prescribed if you have congestive heart failure to prevent potential exacerbations.

How to prevent abnormal phlegm production or colors

Sometimes, discolored phlegm is inevitable, depending on the cause. However, there are some things you can do to try and prevent conditions that may cause phlegm discoloration.

Practice good hygiene

This may seem like a silly and obvious recommendation, but it can be helpful. Practicing good hygiene, such as frequent hand washing, can be helpful in preventing acute respiratory infections, especially during peak flu season.

Smoking cessation

If you are a smoker, you are at an increased risk of developing lung cancer and chronic lung disease such as COPD. All of these factors can cause discolored phlegm. The lungs can heal themselves and regenerate healthy lung tissue after quitting smoking, reducing your risk of chronic associated lung complications. If you are having trouble quitting on your own, your doctor can help discuss different cessation techniques.

Avoid triggers

If you live in an area of high air pollution, wearing a mask outside and using an air filter or air purifier in your house can minimize the amount of pollution you inhale. If you are exposed to workplace hazards such as coal dust or asbestos, you should always wear a respirator mask to minimize the risk of inhaling dangerous material.

Managing phlegm

Understanding the color of your phlegm can provide important information about your lung health and help you decide when medical attention is needed. While many color changes are not serious, some may indicate more serious underlying issues requiring a second look. Color changes lasting more than a week or those associated with symptoms such as shortness of breath, fever, or blood in the sputum should not be ignored.

General Medicine follows a strict editorial process, including using real experts to write our articles, vetted primary sources, fact-checking, a secondary medical review, and updates as necessary. This article was medically reviewed and fact checked by Dr. Jennifer Nadel, MD.

Sources

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