 The aim of this study is to compare two licensed asthma inhalers and to then evaluate the safety of reducing treatment when patients asthma is in control. The inhalers used in this study are the Seretide 250 Evohaler, which is widely used in UK, and a recently licensed inhaler called Flutiform. National guidelines recommend that asthma medication should be increased when patients are experiencing worsening of their asthma, and reduced when asthma is in control. However, it is likely that in daily clinical practice some patients are over-treated. It is therefore necessary to conduct more studies which demonstrate that reducing treatment dosage can be done safely. 