Chronic Bronchitis Chronic bronchitis is an inflammation or irritation, of the airways in the lungs.
Airways are tubes in the lungs that air passes through.
They are also called bronchial tubes. When the airways are irritated, thick mucus forms in the tubes. The mucus plugs up the tubes and makes it hard for one to get air into the lungs. Causes Cigarette smoking is the main cause of chronic bronchitis. When tobacco smoke is breathed into the lungs, it irritates the airways which then produce mucus.