Throughout the study patients keep a diary documenting the severity of their nasal and ocular symptoms of allergy. Every morning and every evening they use a 4-point scale (0 = no symptom, 1 = mild, 2 = moderate, 3 = severe) to rate nasal obstruction, rhinorrhea, nasal itching, sneezing and ocular complaints they experienced during the preceding 12 hours. Furthermore they report adverse events and intake of drugs inclusive of rescue and (during treatment period) study medication.