Asthma is a chronic (long lasting) lung condition that causes coughing, wheezing, and breathing problems. It happens when inflammation and changes in the lungs reduce the flow of oxygen into the blood, making it hard to breathe. Watch this animation to learn about the common causes, symptoms, medicines, as well as the different types of asthma: mild, moderate and severe.

To diagnose asthma, your doctor will ask you a few questions about your medical and family history, examine you, and do lung tests and other tests to measure how well your lungs are working. This animation explains spirometry, methacholine challenge test, exhaled nitric oxide test, x-rays and other scans, blood tests, and bronchoscopy. If you do have asthma, your doctor will also assess the severity of your asthma. There are 4 main levels, or grades, of asthma: intermittent, mild, moderate, and severe. This animation also explains common triggers for asthma and how best to minimize their impact on your life.