Bronchitis is an inflammation or infection of the bronchioles, which regulate the flow of air through the respiratory system into the lungs. It can be acute or chronic. Acute cases of bronchitis can result from a bacterial infection, or as a complication of a severe cold or bout of the flu. Chronic bronchitis occurs when this inflammation becomes constant, and is a common side effect of smoking and exposure to air pollutants or occupational air impurities. Decongestants, expectorants and cough suppressants may be used to treat both acute and chronic cases, while antibiotics are needed to treat bacterial cases. Smoking cessation is strongly recommended in individuals whose bronchitis is the result of tobacco use.