The chronic inflammation of the bronchi in the lungs is termed as chronic bronchitis. It results in persistent cough accompanied by mucus and sputum (phlegm) for a period of three months for consecutive two years. Shortness of breath and wheezing are also reported in patients of the diseases.

The major cause of chronic bronchitis is tobacco smoking, which incidentally is the culprit behind a host of other diseases. Long term fume inhalation and pneumoconiosis are the other two major reasons of chronic bronchitis.
Presence of dry cough, wheezing, breathing sounds and prolonged exhalation is accepted as evidence of the disease.