This cold and flu season, you may be looking for clues you're getting better anywhere you can find them, even in the color of your snot.

First, it’s important to know that fish are covered in a thin layer of mucus. This slimy coating (it is also called a “slime coat”) is known to keep fish healthy by warding off pathogens.

When a person has black or dark-colored mucus, they may have inhaled potentially harmful pollutants. Coughing up black mucus may also be due to an underlying infection or condition. Mucus serves ...

Every surface in our bodies not covered in skin is lined with a protective layer of mucus—a slimy network of proteins that acts as a physical barrier against bacteria and other infectious agents.

A telltale sign you’re getting sick is excess mucus, and if you’ve ever been desperate to stop coughing and sneezing, you’ve likely examined your mucus color, from yellow to green ...