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Asthma Lexicon: The Color Of Sputum

So, you are producing sputum, often called mucus. When you do this, you should look at it. I know, it’s gross! Still, the color of your sputum can help your doctor diagnose you. It can help your doctor determine what is wrong with you. What do the different colors of mucus mean?

The different colors of sputum (mucus)

    • Clear. It’s the normal color of mucus.1
    • White. It may indicate airway inflammation. It’s white because it contains white blood cells. These cells are recruited to the lungs as part of the asthma response. Asthma is an abnormal immune response. This means white blood cells are abnormally recruited to airways, and not in response to an infection. The mucus probably includes eosinophils. It may also include neutrophils. So, white usually means there is no infection. It’s a common color of asthma sputum.2-4
    • Thick white. This may be the color of sputum when you have GERD. It’s the color of mucus plus airway cells plus white blood cells plus regurgitated stomach contents. It may be frothy. It’s often the only symptom of GERD. Another sign of GERD is a cough at night, or while lying down. Keep in mind that GERD may be an asthma trigger.4
    • Colorful sputum. This is any color other than clear or white, such as yellow, green, or brown. It’s an indicator that germs (bacteria or virus) are in present in the sputum. Colorful sputum shows how long bacteria is present in airways. It generally consists of the bacteria plus a combination of cells, such as from surrounding tissue, white blood cells, and red blood cells.4
    • Green. It’s a sign that bacteria and pus is present in the sputum. Pneumonia is caused by bacteria. It causes pus build-up in the alveoli. So, it may produce green sputum. The green color may also be from nasal drainage. So, it can also be a sign of an upper airway infection, such as sinusitis. It can also be an indicator that an infection has been around for a while. So, it may also indicate conditions such as chronic bronchitis, bronchiectasis, and cystic fibrosis.4-5
    • Yellow. It’s a common color in people with chronic bronchitis (COPD). It tends to be thick. It can indicate a bacterial infection.1-3
    • Yellow. It may indicate a cold or infection. Generally, yellow mucus is no reason to be concerned; it means your body is fighting whatever is trying to make its way in. Yellow-colored sputum is not usually associated with asthma.6
    • Brown. Don't panic - generally, brown mucus is due to the presence of dried blood. It may be from breathing in something brown as well, such as dirt or smoke. However, if you are coughing up brown mucus, you may have bronchitis or pneumonia and should reach out to your doctor.5,6
    • Rust. It may also indicate an infection. It may indicate pneumonia.1,5,7
    • Brown plugs. This may indicate allergic bronchopulmonary aspergillosis.2
    • Pink. Your mucus may be pink if you have some lingering blood in your nasal cavity.6 Pink mucus may indicate the breakdown of eosinophils, which can be observed in people with allergies.4
    • Red. Similar to pink mucus, red mucus may also be a cause of extra blood in the nasal cavity.6 It usually indicated the presence of red blood cells. It could also be a sign of an infection, such as pneumococcal pneumonia, or another condition not related to asthma.8
    • Gray or black. Dark, gray-black sputum is most likely to be seen in people who smoke, not specifically in people with asthma. So, I won't delve into it here.4


If your sputum is colorful, your doctor may want a sample. You will likely be asked to spit a sample into a cup for further testing. Tests can determine what cells and/or germs are present in your mucus. This can help your doctor determine how best to treat you.

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