Two doses of triprolidine (2.5 mg t.i.d. and 1.25 mg t.i.d.) were compared with placebo in 32 patients suffering from allergic rhinitis. Triprolidine 2.5 mg t.i.d. was statistically significantly better than placebo (p less than 0.05) in reducing the symptoms of sneezing and eye irritation. Neither dose of triprolidine produced significant drowsiness during the second week of treatment.