“Nasal mucus that would necessitate a visit to your doctor may include frequent nosebleeds, nasal congestion that doesn’t go ...

If your mucus is gray or black... …you likely inhaled dark-colored particles, like smoke from a fire or heavy exhaust. Regular smokers can also blow out darker ...

Lower respiratory infections such as bronchitis and pneumonia can produce ... airways of infection or irritants. The color and consistency of expelled mucus provide important diagnostic information.