Comparison of the Effects of Desloratadine and Placebo in the Relief of Nasal Symptom Scores in Subjects With Seasonal Allergic Rhinitis to Cypress Pollen (Study P02836)

Inclusion Criteria: * Patients must demonstrate their willingness to participate in the study and comply with its procedures by signing a written informed consent. * Patients must be \>=18 years of age, of either gender. * Women of childbearing potential (includes women who are less than 1 year postmenopausal and women who become sexually active) must be using or agree to use an acceptable method of birth control (e.g. hormonal contraceptive, medically prescribed intrauterine device, condom in combination with spermicide) or be surgically sterilized (e.g. hysterectomy or tubal ligation). Women of childbearing potential who are not currently sexually active must agree and consent to use one of the above-mentioned methods, should they become sexually active while participating in the study. * Patients must be in good general health; i.e., they must be free of any clinically significant disease (other than SAR to cypress pollen) that could interfere with study evaluations. * Patients must understand and be able to adhere to the measurement, dosing and visit schedules, and agree to report concomitant medications and adverse events to the investigator or designee. * Patients must have at least a two-year history (self-reported being acceptable) of intermittent allergic rhinitis specifically from January to March * Patients must be clinically symptomatic with SAR to cypress pollen at Visit 2 (Day 0): the total (nasal + non-nasal) symptom score must be \>=8 with a nasal congestion score \>=2. Patients may be rescheduled up to two additional times for the qualifying visit if they do not meet the minimum symptom scores * A positive skin prick test and / or positive cypress-specific IgE by RAST (\>= class 2). These tests should have been performed within 24 months before Visit 1 * Women of childbearing potential must have a negative urine pregnancy test at Visit 2 (Day 0). Exclusion Criteria: * Women who are pregnant or nursing. * Patients who have not observed the designated washout periods for any of the prohibited medications. * Patients with rhinitis medicamentosa. * Patients who have had an upper respiratory tract or sinus infection that required antibiotic therapy within 14 days prior to Visit 1 (screening / consent) or patients who have had a viral upper respiratory infection within 7 days prior to Visit 2. * Patients who have nasal structural abnormalities, including nasal polyps and marked septal deviation, interfering significantly with nasal airflow. * Patients with a history of hypersensitivity to desloratadine or any of its excipients. * Patients who are staff personnel directly involved with the administration of this study. * Patients previously randomised in this study. * Patients having used any investigational drug in the last 30 days prior to Visit 1. * Patients who have any current evidence of clinically significant haematopoietic, metabolic, cardiovascular, immunological, neurological, haematological, gastrointestinal, hepatic, renal, psychiatric, cerebrovascular or respiratory disease, or any other disorder which, in the judgment of the investigator, may interfere with the study evaluations or affect patient safety.