Colors of Mucus (Phlegm, Sputum)
Phlegm may be clear (white), yellow/green, brown, grey, black, pink, orange, containing red streaks, or frothy.
Phlegm is mucus (sputum) coughed up from the chest. It reveals inflammation in the respiratory organs below the vocal cords (voice box, windpipe, bronchi and lungs). From the color and density of phlegm, and accompanying symptoms, its cause may be suspected.