A group of 20 patients with moderate bronchial asthma aged 18 through 65, previously treated with Becotide inhaler for 4 weeks was given Serevent in regular dosage for 4 weeks. Serevent efficiency was assessed clinically and functionally (MEVS, IPB). A progressive improvement of all clinical and functional parameters was obtained following the treatment. The evolution was unsatisfactory with 3 cases which entered the group with advanced asthma condition. No adverse reaction of tachyphylaxis manifestations were recorded. Drug adequacy was perfect. The final results place Serevent among elective bronchodilators in long-time ambulatory treatment.