 - Must be skin test positive to ragweed within the last 15 months with at least a moderate reaction as defined by a wheal 7 mm greater than the diluent wheal after intradermal skin test or a wheal 5 mm greater than the diluent wheal after skin prick test. A skin test performed in the previous 15 months may be used to qualify the patient if it was performed at the investigators site and recorded in the subjects medical record 