OC000459 Dose Finding Study in Hay Fever Sufferers.

Inclusion Criteria: * Males and females aged 18 to 50 years with a history of symptoms of grass pollen related allergic rhinitis within the previous two years. * Females of childbearing potential (i.e. having had a menstrual period within two years prior to the date of screening) must practise two forms of contraception and must have a negative pregnancy test (blood or urine) at screening. * Acceptable contraception includes the use of TWO of the following: * oral contraception (i.e. the Pill); * intrauterine device (an IUD or 'Coil'); * barrier contraception (i.e. condoms or diaphragm/cap); * transdermal patch Exclusion Criteria: * Medical conditions likely to affect the outcome of the study. * Nasal conditions likely to affect the outcome of the study, i.e. nasal septal perforations, nasal polyps, sinus disease, chronic nasal obstruction, or other nasal diseases as determined by the principal investigator or designee. * Presence of any respiratory disease other than a history of mild stable asthma not requiring treatment and associated with normal lung function (defined as FEV1 ≥ 90% predicted for height and age). * Immunotherapy treatment course in the past 28 days * Use of inhaled or local corticosteroids in the past 28 days.