Inflammation of the bronchial tubes.

Acute bronchitis is a clinical diagnosis for an acute cough based on medical signs and patient-reported symptoms. Most cases of bronchitis are caused by viral infections and most symptoms of acute bronchitis last for up to 2 weeks. The cough can last for up to 8 weeks in some people.

Chronic bronchitis is an ongoing cough with mucus most days of the month for three months out of the year. This goes on for at least two years.

Chronic bronchitis is often part of chronic obstructive pulmonary disease (COPD). Both chronic bronchitis and COPD are most often caused by cigarette smoking.