In a randomized, double-blind, double-dummy, crossover study consisting of two 1-month periods with a 2-week ‘run-in’ we compared the effects of a combination of fenoterol with ipratropium bromide (Duovent®, Boehringer Ingelheim) and salbutamol administered by standard metered dose inhalers in conventional dosage in young adults with nocturnal asthma. Seventeen patients were studied, all were aged between 19 and 35 years and showed ‘morning dip’ associated with nocturnal symptoms of cough, wheeze and breathlessness. They recorded morning and evening peak flows and symptoms of nocturnal asthma on diary cards. Over the 10 weeks of the study there was no difference betwen Duovent and salbutamol in any of the parameters measured