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 mucus because of the tar or other toxic ...

But there’s probably a good reason you have that cough — and it can tell you a lot about what’s going on in your body.

In a recent, cross-institutional study, researchers report that healthy human airways are at higher risk for dehydration and ...