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.

Inclusion Criteria:

• Skin test positive for the grass pollen allergen used in the chamber at Screening or within the prior 12 months.

• A negative urine pregnancy test at Screening and at monthly intervals for female subjects of childbearing potential.

• The following minimum scores at an evaluation time point during each of the 120-minute screening period challenge sessions:

  1. Nasal Congestion Score of at least 2 (moderate);
  2. Total Nasal Symptoms Score of at least 6;
  3. Total Non-nasal Symptoms Score of at least 2.

• Freedom from any clinically significant disease, other than SAR, that would interfere with the study evaluations.

Exclusion Criteria :

• An upper or lower respiratory tract infection within 4 weeks before Screening.
• Dependence upon nasal, oral, or ocular decongestants, nasal topical antihistamines, or nasal steroids, in the opinion of the investigator.
• A known potential for hypersensitivity, allergy, or idiosyncratic reaction to the study drug or excipients.