Bronchitis is an illness where the tubes that carry air to your lungs, called bronchi, become swollen and irritated. When you have bronchitis, these airways get inflamed and produce extra mucus, which triggers coughing as your body tries to clear it out. The cough often sounds wet or raspy, and you might feel tightness in your chest.

There are two main types. Acute bronchitis comes on suddenly, usually after a cold or flu, and typically clears up within a few weeks. Chronic bronchitis is more serious: it lasts for months or even years and is often caused by smoking or breathing polluted air over long periods.

When someone has bronchitis, they often need rest and fluids while their body fights the illness. Doctors sometimes prescribe medicine to help with breathing or coughing. Bronchitis can spread when it’s caused by a virus or bacteria that moves through coughs and sneezes, which is why covering your mouth and washing your hands helps protect others.