An open clinical trial to establish the efficacy of fenoterol (Berotec) aerosol bronchodilator was conducted on 11 severely affected asthmatic patients in a Sydney general practice. Berotec was found to be an effective bronchodilator with a very rapid onset of action. Over 60% of the maximum response from a single puff dose was evident one minute after inhalation. Berotec also has a long duration of action, as there was statistically significant bronchodilator effect six hours after inhalation, and even at eight hours after inhalation, improvement on baseline values was demonstrated. Berotec appears to have significant advantages over other bronchodilators.