This is a randomized, double blind, active and placebo controlled, 4 way crossover study in patients with seasonal allergic rhinitis. Patients will receive a single dose of bilastine 20 mg, Cetirizine 10 mg, Fexofenadine 120 mg, and placebo in the Vienna Challenge Chamber.

The objective of the study is to determine the effect of a single dose of bilastine 20 mg on nasal symptoms of allergic rhinitis provoked by spending 4 hours in the Vienna Challenge Chamber . This effect will be compared to that action of Cetirizine 10 mg, Fexofenadine 120 mg, and placebo. To explore the onset of action, patients will receive study drug two hours after the start of the provocation on Day 1.Patients will remain in theVCC for an additional four hours. On Day 2, patients will return to the VCC post-dose hours 22-26.

Inclusion Criteria:

• Have a history of seasonal allergic rhinitis
• Have a positive (as defined in the protocol) skin prick or RAST test within 12 months prior to the screening visit

Exclusion Criteria:

• Have a clinically significant illness or disease
• Have unstable asthma
• Has participated in a clinical trial 30 days prior to the screening visit