Mucus, a fluid in your upper respiratory system, is usually clear. But a number of health conditions can cause it to turn brown. Also known as brown phlegm or sputum, brown mucus can be due to a range ...

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.