Bronchitis is an infection caused by virus and bacteria. It can also be termed as a respiratory disease where mucous membrane of the lungs bronchial passage becomes inflamed. During bronchitis the irritated membrane swells and becomes thicker which narrows down or shuts the tiny airways in the lungs and leads to cough, breathlessness and thick phlegm. Bronchitis is either acute or chronic. Acute bronchitis can be termed as a medical condition which comes quickly and lasts only for a short period of time. It is mainly caused by one of the various viruses that infect the respiratory tract and attacks the bronchial tubes.

Besides virus there are certain bacteria as well which can cause acute Bronchitis. This type of bronchitis develops during the course of upper respiratory infection as in common cold or influenza. Chronic bronchitis is termed as a chronic obstructive pulmonary disease which causes productive cough and lasts for about a period of 3 months to 2 years. Air pollution, cigarette smoking and exposure to irritants are some of the most common causes that results in chronic Bronchitis. People with this type of bronchitis are more susceptible to have bacterial infection of the airway and the lungs as in pneumonia.