Inhaled corticosteroids are the only class of asthma medication that can reduce symptoms, improve lung function, reduce the frequency of severe exacerbations, including hospital and ICU admissions, and decrease the risk of mortality. The therapeutic dose range for all clinical outcome measures in adults is 100 to 1000 mg/d of beclomethasone dipropionate or budesonide, or 50 to 500 mg/d of fluticasone propionate. Doses in excess of this range are not recommended for routine use because they are likely to increase the risk of systemic side-effects without further major improvement in efficacy. The recommendations are qualified by the recognition that there is considerable individual variability in the response to inhaled corticosteroids in asthma, which would suggest that some patients might obtain greater benefit at higher doses, just as some might obtain maximum benefit at lower doses.