A higher-than-normal amount of phlegm can build up in your nose, throat, and lungs when you are sick. This build-up may cause coughing and discomfort. Bloody, brown, white, yellow, or green phlegm ...

Coughing up thick, green mucus may mean a bacterial or, less often, viral infection, but that's not always true. You constantly breathe in bacteria, some of which are harmless, through your nasal ...