Asthma affects 300 million people in the world, more than 25 million people in the United States have asthma and about 5.4 million people in the United Kingdom are currently being treated for asthma. Despite the prevalence of asthma, there is very little knowledge about the disease. What do you know about asthma is a practical guide that will help you understand asthma, what you can do as a sufferer or what support you as parent, family, friend or carer can give to someone living with asthma to enable them learn how to manage their symptoms so they could live healthy, active and symptom-free lives.