What is chronic bronchitis?

Chronic bronchitis is an inflammation, or irritation, of the airways in the lungs. Airways are the tubes in your lungs that air passes through. They are also called bronchial tubes.

When the airways are irritated, thick mucus forms in them. The mucus plugs up the airways and makes it hard for you to get air into your lungs. Symptoms of chronic bronchitis include a cough that produces mucus (sometimes called sputum), trouble breathing and a feeling of tightness in your chest.

What causes chronic bronchitis?

Cigarette smoking is the main cause of chronic bronchitis. When tobacco smoke is inhaled into the lungs, it irritates the airways and they produce mucus. People who have been exposed for a long time to other things that irritate their lungs, such as chemical fumes, dust and other substances, can also get chronic bronchitis.