A 30-year-old woman produced a single mass of gray material from her nose during a particularly forceful sneeze several hours before presenting to our clinic. She asked that the material be submitted ...

A new study shows that the body’s early immune response, not the virus itself, often determines how severe a rhinovirus cold becomes.

Rhinovirus is the most common cause of the common cold and is also a frequent trigger for breathing problems in people with asthma and other long-term lung conditions. The study looked at what happens ...

Your chances of catching a cold—and how miserable it feels—may depend more on your body than on the virus itself.

When a rhinovirus, the most frequent cause of the common cold, infects the lining of our nasal passages, our cells work together to fight the virus by triggering an arsenal of antiviral defenses. In a ...

Medically reviewed by Amelia MacIntyre, DO Smoking can lead to brown mucus due to tar build-up in the lungs. Inhaling pollutants and toxins can cause brown mucus. Lung infections from bacteria and ...