Oxitropium bromide is a derivative of scopolamine and is an anticholinergic drug. Twenty asthmatics completed the study in which they received, in randomised double-blind fashion, placebo, ipratropium bromide 80 micrograms, and oxitropium bromide 200 micrograms. The patients recorded peak expiratory flow immediately before inhalation and up to 10 h afterwards. PEF were significantly higher than placebo between 10 min and 10 h, for both active treatments. There were no significant differences between values on oxitropium bromide and ipratropium bromide at any time points. Side effects were minimal and oxitropium bromide is an effective bronchodilator in asthma.