Ebastine is an H1 antihistamine. Using a double-blind, parallel group randomized study design, the efficacy and the tolerability of oral ebastine (10 mg daily escalating to 40 mg daily according to clinical need) was compared over 4 weeks during 1986 with matching placebo in 40 general practice patients suffering from hayfever. Ebastine (19 patients) was more effective (P less than 0.05) than placebo (21 patients) against symptoms of running nose, itching nose, sneezing and blocked nose. Ebastine was superior to placebo in respect of the total symptom score as well as when judged by the investigators' and the patients' opinion of overall efficacy. Ebastine caused few adverse events, none of which resulted in a patient being withdrawn from treatment. Significantly more patients were withdrawn because of inefficacy from the placebo (n = 12) than from the ebastine (n = 3) treatment group (P less than 0.02). It is concluded that ebastine (10-40 mg daily) is an effective and well tolerated treatment for hayfever.