The purpose of this study is to evaluate how well mometasone furoate nasal spray (MFNS) works to relieve SAR symptoms compared to Placebo when symptoms are induced in a chamber setting. Evaluation will be based on subjects self-assessed nose symptoms. Other areas the study will evaluate are: 1) changes in eye symptoms (ocular symptom severity score) after dosing 2) how long MFNS works in relieving the nose (nasal) and eye (ocular) symptoms after 7 daily doses, 3) measurements of nose (nasal) blockage (obstruction), and 4) measurements of the subject's opinion of the study drugs by asking different questions. This study is could last up to 53 days for some subjects.

Inclusion Criteria:

• Willing to participate and to adhere to dose and visit schedules
• 18 to 65 years, either sex, any race
• 2-year history of SAR, being symptomatic during the last 2 ragweed seasons
• Skin test positive to short ragweed allergen at screening, or positive within 12 months
• Women must practice adequate contraception: Females of childbearing potential (including women who are less than 1 year postmenopausal and women who will be sexually active during the study) must agree to use a medically accepted method of contraception or be surgically sterilized prior to screening, while receiving protocol-specified medication, and for 30 days after stopping the medication. Women who are postmenopausal for >1 year (ie, women who have experienced 12 consecutive months of amenorrhea) will be exempted from the use of contraception during the study.; Acceptable methods of contraception include condoms (male and female) with or without a spermicidal agent, diaphragm or cervical cap with a spermicidal agent, medically prescribed intrauterine device (IUD), oral or injectable hormonal contraceptives, and surgical sterilization (eg, hysterectomy or tubal ligation)
• Negative pregnancy tests during study

Exclusion Criteria:

• Compromised ability to provide informed consent
• Nasal abnormalities, including large nasal polyps, and marked septum deviation that interferes with nasal airflow at screening
• Recent (within the last 2 weeks) or unhealed nasal septum ulcers, nasal surgery, or nasal trauma
• Unstable asthma which cannot be controlled with inhaled short-acting beta-2 agonists
• Diagnosed with sinusitis within the previous 2 weeks
• Is initiating or is currently on advanced immunotherapy
• If on immunotherapy (desensitization therapy), the subject must be stable and should not receive an increase in dose during the study. Subjects may not receive desensitization treatment within 24 hours prior to a study visit
• Is currently on or has been on an antihistamine, decongestant (topical or systemic) or a nasal inhaled corticosteroid during the 14 days prior to the first priming visit
• Unable to refrain from regular use of nasal, oral or ocular decongestants, nasal topical antihistamines, or nasal steroids
• Failed the designated washout periods for any of the prohibited medications
• Upper or lower respiratory tract or sinus infection that required antibiotic therapy or a viral upper or lower respiratory infection within 14 days prior to screening
• Is allergic to or has sensitivity to the study drug or its excipients
• Used any investigational product within 30 days before enrollment or any antibodies for asthma or allergic rhinitis in the past 90 days
• Subject has Chronic obstructive pulmonary disease, Alcohol abuse, Rhinitis medicamentosa