We compared the incidence of Candida infection, Candida colonization, and reduction in oral prednisone dose in patients with asthma treated with beclomethasone dipropionate delivered by metered-dose inhaler (MDI) alone and MDI plus Aerochamber. Group M contained 18 patients treated with beclomethasone, four actuations four times a day (672 micrograms/day), delivered by MDI alone. Group A contained 18 patients treated with the same dose of beclomethasone delivered by MDI plus Aerochamber. In group M, four of 18 patients had Candida infection, 12 of 18 patients had Candida colonization, and six of 18 patients were completely removed from oral prednisone. In group A, 0 of 18 patients had Candida infection (p = 0.05), six of 18 patients had Candida colonization (p less than 0.05), and 12 of 18 patients were completely removed from oral prednisone (p less than 0.05). We conclude that beclomethasone delivered by MDI plus Aerochamber is more efficacious in reducing oral prednisone dependency and produces less Candida infection and colonization than beclomethasone delivered by MDI alone.