Inhaled corticosteroids are considered by many to be the anti-inflammatory therapy of choice in adult asthma, given their remarkable efficacy and apparent safety. They are presently being prescribed to more patients, at larger doses, and for longer periods of time than ever before. Oropharyngeal candidiasis and dysphonia are the most commonly recognized adverse effects of therapy, but these topical phenomena cause no significant morbidity and are easily managed. By contrast, there is now increasing concern about the potential systemic effects of inhaled corticosteroids. These putative effects may include adrenal suppression, bone loss, skin thinning, increased cataract formation, decreased linear growth in children, metabolic changes, and behavioral abnormalities. Changes in adrenal function have been noted in patients using medications such as beclomethasone dipropionate and budesonide in doses exceeding 1,500 micrograms/day. The clinical relevance of these changes has yet to be clarified. Several short-term and cross-sectional studies have also revealed changes in biochemical markers of bone turnover and retrospective studies have found reduced bone density in asthmatics treated regularly with inhaled steroids. Long-term prospective studies assessing bone density changes remain to be done. Although much controversy exists, there is no unequivocal evidence that conventional doses of inhaled steroids significantly retard bone growth in children. Reports on skin changes, increased cataract formation, and behavioral changes are difficult to interpret because of several confounding factors. Although inhaled steroids should, at the present time, continue to be a recommended therapeutic option to all patients with symptomatic asthma, they should always be used in the lowest dosage compatible with disease control.