In a placebo controlled, randomised, multicentre study the efficacy and safety of multiple doses of acrivastine, a derivative of the antihistamine tripolidine (Actidil) were evaluated in patients exhibiting symptoms of seasonal allergic rhinitis. Over the 10 day treatment period, 103 patients received, twice daily, either 4 mg and 8 mg of acrivastine or a placebo. Three patients withdrew from the study due to poor symptom control and two due to adverse experiences. The reporting of adverse experiences was evenly distributed between the treatment and placebo periods. Acrivastine did not affect the haematological, biochemical or urinalysis screens. Both 4 mg and 8 mg acrivastine alleviated the symptoms of seasonal allergic rhinitis with significant improvements in the symptom scores for sneezing, running nose and the calculated overall score. In addition, 8 mg acrivastine reduced the symptom scores for watery eyes and itchy throat. Acrivastine was both well tolerated and effective in the treatment of seasonal allergic rhinitis.