A community based, prospective study of the value of high dose inhaled therapy for the reduction of the morbidity of asthma has been undertaken. One hundred and sixty adults with airflow obstruction were treated for up to 9 months with increasing doses of salbutamol. Two thirds of the patients also received increasing doses of beclomethasone dipropionate in a 'partially double-blind' manner. The FEV1 rose by at least 10 per cent of that predicted in one third of the total patients and the overall mean domiciliary peak expiratory flow rates rose by approximately 50 l/min-1. All chronic symptoms were abolished in half of the patients and acute attacks of asthma in the majority. Asthma was controlled in a greater proportion of patients more effectively and rapidly by a combination of inhaled steroids and beta agonist than by salbutamol alone, particularly when inhaled steroids were started in relatively high dosage.