Bronchitis is one of the common respiratory diseases, caused by microbes, physical and chemical irritants, or allergies, among other factors. It involves inflammation of the bronchial mucosa. Generally, this condition is not severe. After contracting bronchitis, patients often experience symptoms such as coughing and expectoration. Some patients may also experience fever, chest tightness, and other symptoms. However, in most cases, bronchitis can heal within two to three weeks. In a minority of cases, if it persists, it may develop into chronic bronchitis.