This is a preliminary report on the first half of a study designed to assess the ability of two different spacer devices to improve the results of aerosol steroid treatment in chronic asthmatic patients given budesonide in low and high dosages. The spacers significantly reduced oropharyngeal candidiasis but did not affect dysphonia - possibly because the incidence of the latter was so low throughout the study. The spacers augmented the airway response to budesonide in these patients without materially increasing systemic absorption of the drug (assessed indirectly in terms of the change in blood eosinophil counts). Pretreatment with inhaled terbutaline did not significantly affect the performance of the spacers, either in terms of the airways responses or the amount of budesonide systemically absorbed. When used properly, these spacers can improve the cost effectiveness of aerosol steroid treatment. Since only adults were studied, it is not known whether these findings apply equally well to children with asthma.