The short-term bronchodilator effects of dry salbutamol powder and a pressurized salbutamol aerosol were compared in 22 patients with severe asthma, on 3 consecutive mornings, in a double-dummy cross-over study. Only patients with peak expiratory flow (PEF) rate lower than 250 l/min, were recruited. PEF measurement was employed to assess changes in ventilatory function induced by inhalation of the drugs. No significant difference was found between the PEF changes induced by the dry salbutamol powder (400 micrograms) and the pressurized aerosol (200 micrograms). Both forms of the drug produced a significant rise in mean PEF values. The study shows that even in asthmatic patients with poor ventilation, a dry powder inhaler and pressurized aerosol are effective means of drug delivery to the lungs.