We assessed the systemic effects of budesonide (BUD) and fluticasone propionate (FP) in 23 patients with asthma, using a double-blind, placebo-controlled, double-dummy, and cross-over design. The following five treatments were given in a randomized order for 1 wk with a washout period in between of 2 wk: (1) placebo; (2) FP, 200 micrograms twice a day, inhaled from a Diskhaler; (3) FP, 1,000 micrograms twice a day, inhaled from a Diskhaler; (4) BUD, 200 micrograms twice a day, inhaled from a Turbuhaler; and (5) BUD, 800 micrograms twice a day, inhaled from a Turbuhaler. The primary variable was the area under the curve of serum cortisol versus time (AUC0-20), derived from serum samples taken every 2 h over a 20-h period following the last evening dose at 10:00 P.M. The lower doses of BUD and FLU did not cause any adrenal suppression. Compared with placebo, however, FP (1, 000 micrograms, twice daily and BUD (800 micrograms, twice daily) decreased the AUC0-20 by 34 and 16%, respectively. Fluticasone (1,000 micrograms, twice daily) was more suppressive than BUD (800 micrograms, twice daily) (p = 0.0006). The FEV1, measured the morning after the last inhalation, was significantly higher after the active treatments, compared with placebo (p < 0.02), but did not differ between all active treatments. We conclude that high doses of BUD and FP (in particular the latter), inhaled via their respective dry powder inhalers for 1 wk, result in a measurable systemic activity in patients with asthma.