In a double-blind trial, beclomethasone dipropionate inhaled as a dry powder in doses of 200 μg three times a day was compared with the conventional aerosol of 100 μg three times a day, each for a period of 4 weeks. Neither the dry powder nor the aerosol showed any significant advantage over each other in terms of ventilatory function. Plasma cortisol levels were unaltered with the two medications in spite of the doubled dose of the corticosteroid powder. Choice of one or the other method of administration of medication depended on patient preference and the ease with which he could familiarize himself with either technique.