Add Yahoo as a preferred source to see more of our stories on Google. Yellow snot is gross, but does it mean you have an infection? Here's everything you need to know about it. Snot, mucus, phlegm ...

Mucus is a thin, slippery fluid that lines the nose, throat, and other passages to trap dust and germs. Phlegm is a thicker type of mucus produced in the lungs to catch and remove harmful particles ...