An open cross-over trial comparing astemizole with intra-nasal aqueous beclomethasone dipropionate was carried out in forty-five perennial rhinitis patients attending a S.W. London general practice. Each drug was given for 12 weeks, separated by 4-8 weeks without medication. The principal outcome measure was a 7-day symptom diary completed by patients during weeks 4, 8 and 12. Patients were skin tested to seven common inhalant allergens. Half the patients beginning either regime failed to respond adequately within 2 weeks. Doubling the dose in these patients achieved satisfactory symptom control in an additional 67% on beclomethasone dipropionate and 45% on astemizole. Symptom diary scores showed beclomethasone dipropionate to be significantly more effective than astemizole in the treatment of skin test negative patients; but the two drugs were of equal benefit in the treatment of skin test positive patients. Sneezing and rhinorrhoea were the same on both drugs, but nasal blockage tended to be less severe on beclomethasone dipropionate. There was no significant difference between drugs in the frequency or duration of side effects. Beclomethasone dipropionate and astemizole are equally effective in the symptomatic treatment of atopic perennial rhinitis, but beclomethasone dipropionate may offer superior symptom relief in non-atopic perennial rhinitis.