This medicine treats people suffering from hay fever (seasonal allergic rhinitis), perennial allergic rhinitis (a similar condition to hay fever caused by allergies, that continues throughout the year) and urticaria (swelling, redness and itchiness of the skin). Antihistamines like cetirizine relieve the unpleasant symptoms and discomfort associated with the above conditions, such as sneezing, itchy, runny and blocked nose, itchy, red and watering eyes and itchy skin rashes.