Phlegm color can change when you’re ill or exposed to smoke and pollution.
Normal phlegm is clear.
It can also be a sign of a minor infection.
Illustration by Michela Buttignol for Verywell Health
Allergens and irritants trigger your body to build up the mucus in your nasal passages.
As the phlegm accumulates, it may cause a runny nose.
For both asthma and allergies, you could prevent symptoms by avoiding triggers.
Allergy symptoms may be treated with over-the-counterantihistaminesor prescription medication when needed.
For immediate relief, use saline nasal rinses to thin out phlegm.
Green Phlegm
Phlegm related to an infection can start out yellow but may become a darker green.
The color change happens when there are a lot of white blood cells and other debris in the mucus.
Red Phlegm
Bright red or dark red phlegm is also calledhemoptoicsputum.
People who experience pulmonary edema say it feels like drowning as they struggle to breathe and get enough oxygen.
Lung infections that cause brown phlegm include COPD andemphysema.
Treating these conditions may allow you to manage the phlegm.
Black Phlegm
Black or gray phlegm is also calledmelanoptysis.
This is a very rare occurrence.
See a healthcare provider anytime you cough up black-colored mucus.
Changes in the normal clear color of phlegm may indicate an illness or exposure to irritants.
For black or brown phlegm, see your provider right away.
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