In the first phase, subjects with a history of grass pollinosis, with positive skin tests to grass, will be studied out of season and will be randomized to placebo and active treatment for 4 months. Randomization will be based upon a retrospective Rhinitis Quality of Life Questionnaire regarding their recollection of the worst week of the last pollen season. The intent is to randomize subjects such that the distribution of those with severe versus mild allergy symptoms is equal in both groups. The subjects will be evaluated for their nasal function (patency by acoustic rhinometry) and undergo a nasal provocation test and collection of nasal secretions at the beginning and end of the study. Blood will be drawn and skin tests will be performed at the beginning and end of the study.