Phlegm is naturally clear. So, if your phlegm is a different color, such as yellow or green, you may have a viral or bacterial infection. Brown, red, or black phlegm may be a sign of a more serious ...

Whether you're dealing with a runny nose, cough or congestion, your mucus can help determine if it's a minor bother like a ...

Please provide your email address to receive an email when new articles are posted on . Patients with more purulent sputum had a higher frequency of exacerbations and hospitalizations over 5 years.