Asthma is a long-term disease of the lungs. It causes your airways to get inflamed and narrow, and it makes it hard to breathe. Severe asthma can cause trouble talking or being active. You might hear your doctor call it a chronic respiratory disease. Some people refer to asthma as "bronchial asthma." Asthma is a serious disease that affects about 25 million Americans and causes nearly 2 million emergency room visits every year. With treatment, you can live well. Without it, you might have to go to the ER often or stay at the hospital, which can affect your daily life.