This is a Phase 3, single-dose, investigator-blind, randomized, placebo-controlled, crossover study, conducted at a single site in Austria, outside of the normal grass pollen season. An allergic reaction will be induced by exposing subjects to grass pollen in the Vienna Challenge Chamber (VCC). Subjects will receive a single dose of each of the following treatments according to a randomization sequence: Phenylephrine 12 mg immediate-release capsule, pseudoephedrine 60 mg immediate-release tablet, and placebo capsule. There will be a minimum of a 5-day washout period between each treatment. Subjects will complete symptom evaluations throughout the study. The nasal decongestant effects of phenylephrine will be compared to those of placebo using the subjective symptom evaluations. The safety profile (adverse events and vital signs) of the treatments will also be evaluated.