Bronchitis is a condition that occurs when the lining of your throat that carries air to your lungs becomes inflamed. It can cause an increase in mucus, and it can be either acute or chronic. Chronic bronchitis is more likely to occur in those who smoke. Acute bronchitis is typically cleared up within ten days. While acute bronchitis can be caused by a variety of illnesses, it is still contagious. The illness is very common ...