The dose-response effects of inhaled beclomethasone dipropionate (BDP) and budesonide (BUD) administered b.i.d. with the aid of metered dose aerosols were studied in 128 patients (67 men and 61 women, mean age 53 years) suffering from asthma bronchiale. The study was designed as a multi-centre, double-blind, four-period cross-over study, followed by a single-blind double placebo period. BDP was administered in doses of 400 and 1000 micrograms, and BUD in doses of 400 and 800 micrograms. The results in terms of peak expiratory flow (PEF) in the morning and evening, daily symptoms score and use of inhaled beta 2-agonists did not reveal any clinically significant differences between the drugs or between high (800 micrograms BUD, 1000 micrograms BDP) and low (400 micrograms BUD/BDP) doses. However, statistically significant differences were recorded for the corresponding parameters when comparing the placebo with preceding steroid periods. Adverse effects consisting mainly of oropharyngeal candidiasis, hoarseness and cough occurred in 54 of 468 treatment months (12%). The carry-over effects of inhaled steroids are longer lasting than was previously assumed.