Brown Mucus/Phlegm: Symptoms, Causes, and Treatment
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Coughing up Brown Mucus, Causes for Different Phlegm Colors
Don't judge your mucus by its color - Harvard Health
Phlegm and Mucus: How to Get Rid of It
Brown Mucus/Phlegm: Symptoms, Causes, and Treatment
Coughing Up Green or Yellow Phlegm
Coughing up phlegm but not sick: Causes, phlegm colors, and more
Is brown phlegm, resulting from smoking, indicative of cancer? - Poe
What is a Mucus? Symptoms, Causes & Treatment
Persistent Cough: Possible Causes