Problems in the lungs can cause phlegm to change color. Green or yellow phlegm can occur with an infection, but brown phlegm might indicate bleeding in the lungs. Phlegm is a type of mucus that comes ...

Phlegm is naturally clear. So, if your phlegm is a different color, such as yellow or green, you may have a viral or bacterial infection. Brown, red, or black phlegm may be a sign of a more serious ...

The color of the phlegm from patients with the lung disease bronchiectasis can indicate the degree of inflammation in their lungs and predict their future outcomes, according to new research presented ...