Betamethasone valerate aerosol given in doses of 100 μg into each nostril twice daily was compared with a placebo in a double-blind, cross-over trial involving thirty patients with seasonal rhinitis. Patients recorded symptoms of eye irritation and watering, sneezing, rhinorrhoea, and nasal blockage, on a diary card. Analysis of the symptom scores showed that nasal symptoms were significantly better on betamethasone valerate than on placebo (P<0.01) and that nasal blockage in particular was improved (P<0.001). The patients’preference was significantly in favour of the active compound (P < 0.02) and no side-effects were noted. It is concluded that betamethasone valerate offers a safe and effective form of treatment for seasonal rhinitis.