Cystic fibrosis (CF) is an inherited disease in which the body makes very thick, sticky mucus. The mucus causes problems in the lungs, pancreas, and other organs. People with cystic fibrosis ...

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

People with cystic fibrosis have thick, sticky mucus that blocks passages in their lungs, making it difficult for them to breathe and predisposing them to infections. New drugs are under development ...