Black mucus is rare. It can be the sign of a fungal infection, or exposure to pollutants such as coal, dust or cigarette ...

Drinking plenty of fluids can help decrease the thickness of phlegm and make it easier to remove. Bloody, brown, white, yellow, or green phlegm may be a sign of an underlying condition or infection.

Mucus is a normal part of the lungs. But smoking and other issues can cause too much mucus to collect there. (Photo Credit: iStock/Getty Images) Your body makes about a liter (approximately 1 quart) ...

Snot is made up of water, proteins, antibodies, and dissolved salts, explains Jonathan Parsons, M.D., a professor in the Department of Internal Medicine at The Ohio State University Wexner Medical ...