If your mucus is gray or black... …you likely inhaled dark-colored particles, like smoke from a fire or heavy exhaust.

This cold and flu season, you may be looking for clues you're getting better anywhere you can find them, even in the color of ...

The mucus plug is a clump or mass of mucus. It can be thick and even solid in some people, or thinner and wetter. The color ranges from white to clear and might be yellowish. The size ranges from ...

Normal mucus often looks clear or white for most people, experts say. But mucus changes color, depending on the individual’s environment, in response to various germs and more, he adds.