The body produces mucus, also known as phlegm or sputum, to protect sensitive tissues in the airways. Changes in the sputum color, thickness, or quantity of phlegm may indicate a health problem, such ...

Coughing up mucus may be a sign of a respiratory infection or lung issue. The color of the mucus may help inform what’s going on. You may be able to clear mucus at home by staying hydrated, using a ...