Acute episodic wheeze related to viral infections is a common and distressing condition and treatment remains unsatisfactory. Although some benefit from the continuous use of inhaled steroids has been demonstrated in young wheezy children, their effect primarily on acute episodes has not been considered. In this study the effect of budesonide (400 micrograms/day) was assessed in a four month double blind parallel trial, in 41 children (0.7-6.0 years) with predominantly episodic viral wheeze. Analysis of the last three months showed no difference between budesonide or placebo in mean daily total symptom score (median values 0.6 and 0.63), episode number (mean values 2.6 and 2.4), or score/episode (mean value 30 and 31). Four months of treatment with inhaled budesonide had no effect on acute episodes of wheeze in this group of children.