This double-blind parallel group study evaluated ketotifen 1 mg bid versus placebo in the treatment of 30 adult seasonally allergic asthmatics during the course of the spring pollen season. Those individuals on placebo had a fall in FEV1 through the pollen season, those on Ketotifen generally did not, and some individuals, in fact, showed improvement. Those patients receiving ketotifen had fewer allergic symptoms, better exercise tolerance, and in general had a better spring. This study demonstrated that ketotifen may have some benefit in the treatment of adult allergic asthma.