Although three effective topical treatments for allergic rhinitis are available, little information to assist the clinician in choosing among them has been reported. Therefore, we conducted a randomized clinical trial to compare beclomethasone nasal solution, flunisolide, and cromolyn with placebo in 120 patients with hay fever during the ragweed season of 1984. We found that all three agents were superior to placebo (P less than 0.001) and that the glucocorticoids were more effective than cromolyn (P less than 0.001). Surprisingly, we also found that these intranasal treatments considerably reduced the symptoms of seasonal asthma. Further study of this therapeutic advantage is needed.