In asthma, inflammation (swelling in the wall) narrows the airway and is the main factor giving rise to asthmatic symptoms of cough, wheeze, shortness of breath and chest tightness. Inhaled corticosteroids (ICS) which are given usually more than once daily are now recommended as first line therapy for most people with asthma. The currently available ICS, such as budesonide (BUD), beclomethasone (BDP) or fluticasone (FP), have been available for many years and have proven to be an important therapy for controlling inflammation and symptoms. However, these drugs can be associated with significant side-effects, especially local effects in the upper airways such as hoarseness and oral candida (thrush infection). The main reputed advantage of ciclesonide (CIC, a new generation of ICS), is its ability not only (as with other ICS) to be delivered locally by inhalation but specifically to the lower airways of the lung in a form which potentially minimises local side-effects. Overall this advantage of CIC could lead to a reduction of local airway side-effects with once daily therapy and thereby improving adherence to therapy. The results from this review indicate that CIC at low to moderate doses improves lung function and reduces asthma symptoms compared to placebo, but the short duration of the studies means that there is a lack of information about the impact on asthma exacerbations. Thus the currently recommended doses of CIC of 100-200 mcg daily would seem appropriate. However, the number of studies in the higher dose range are low and further studies are therefore required in adults and children to determine whether higher CIC doses will give significant benefit without increasing adverse events. It will also be important to determine in clinical studies how CIC compares to the other currently available ICS in terms of efficacy and safety in asthmatic adults and children in order to determine the precise role of CIC therapy in asthma. The published data are insufficient to assess the reputed safety advantage of ciclesonide, and better assessment and reporting in studies is required to address this important question.