Salbutamol dry powder was compared with salbutamol aerosol in 38 asthmatic patients. The study was double-blind and took place over six months. Salbutamol powder in a dose of 200 micrograms per capsule was able to control asthma as well as the aerosol, but some patients needed to increase the frequency of dosage when using the powder. The device used for powder administration, the Rotahaler, was well accepted and was preferred to the pressurized aerosol by one-third of patients. Dry powder administered by Rotahaler allows salbutamol to be given by inhalation to many patients previously using aerosols inefficiently.