Beneficial effects of treatment of viral croup with inhaled corticosteroids and administered with a jet-nebulizer have been reported in recent years. To facilitate such therapy at home and avoid hospitalization, the administration of inhaled corticosteroids with a metered dose inhaler (MDI) with a holding-chamber was studied as a potential alternative. In a hospital-based prospective, double-blind, randomized study, 17 children admitted with croup were treated with either fluticasone propionate MDI (2,000 microg with the Babyhaler spacer) or placebo. The primary outcome variable was the croup symptom score recorded from 0 up to 24 hours. Secondary outcome variables were the need for administration of nebulized corticosteroids with a nebulizer, the need for intubation, and the duration of hospitalization. The administration of the drug with an MDI and spacer was well tolerated in each child. In all children the clinical course was favorable, without any significant differences between the actively treated and placebo-treated group. One child needed additional use of inhaled corticosteroids with a jet nebulizer, despite treatment with fluticasone. Mean duration of hospitalization was 2.6 (1-4) and 2.4 (1-4) days for treatment with fluticasone and placebo, respectively. No undesirable side effects of treatment were reported. In conclusion, this study did not demonstrate therapeutic benefits of fluticasone propionate when administered with an MDI and a spacer compared with placebo. We hypothesize that the lack of effect is probably due to the inadequate deposition of adequate inhaled corticosteroids in the upper airways.