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 ...
The COVID-19 virus spreads via mucus once inside an infected airway, allowing it to reach into the lower lungs, according to a Northwestern Medicine study published in Nature Communications.
Green, yellow, or bloody mucus also warrants a trip to a healthcare provider as you could have a bacterial infection, for example. Other symptoms that may be related to post-nasal drip and need ...