 Method In a cross-over study design of 6 months, 33 children, aged 6-12 years, with doctor diagnosed mild persistent asthma, were treated with extrafine HFA-beclometasone inhaled from an autohaler and HFA-flucticasone inhaled from a discus. Primary outcome parameters of this study were; alveolar NO concentration and bronchial NO flux. Secondary outcome parameters were inflammatory markers in EBC, lung function parameters, symptoms, presence and duration of exacerbations and adverse effects. All parameters were recorded at baseline and after each treatment period. 