Systemic corticosteroid is the first-line-treatment for olfactory dysfunction of sinonasal origin but is afflicted with many side-effects. Topic corticosteroid does not reach the same efficacy but has a remarkable safety profile. In this trial we investigated the efficacy of topic therapy with beclomethasone (BDP) -spray. The drug was applied precisely to the olfactory cleft by a special spraying top-part. In addition we determined extinction and volume of a gelaspon sponge placed in the olfactory cleft to show the difference of the topical spray application. 18 patients with anosmia or hyposmia of different genesis and duration applied BDP-spray twice daily for four weeks. The olfactory function was determined using the TDI score ('Sniffin'-Sticks test battery'). Factors correlated with therapy efficacy were assessed. The median TDI score increased from 13.5 (0-25) at the beginning to 18.5 (1-26) after therapy of four weeks (P = 0.005). The extinction and volume in the moistened sponge was more than two times greater with the top-part than without. The direct application of BDP-spray to the olfactory cleft attained superior therapeutic effects than a usual applied mometasone spray, but did not perform as good as systemic corticosteroid treatment.