A Study Evaluating the Efficacy and Impact on Health-related Quality of Life of Levocetirizine in Adults With Seasonal Allergic Rhinitis

Inclusion Criteria: * Subjects with a history of SAR symptoms * A positive skin prick test at least one grass allergen * Moderate - severe SAR symptoms at baseline * Women of childbearing potential must use a medically acceptable form of contraception * 80% compliance on run in study medication and 80% compliance on completing the diary Exclusion Criteria: * The presence of any clinically significant comorbid disease which may interfere with the study assessments * The presence of renal disease * Pregnant or breastfeeding * Subject is currently participating in another clinical trial * Known hypersensitivity to piperazines or any of the excipients * Intake of medications prohibited before the start of the trial * Subjects who started or changed the dose of immunotherapy * Rhinitis medicamentosa * Subjects with a recent history (within the last 2 years) of drug or alcohol abuse.