Cetirizine Dihydrochloride is an antihistamine medication that relieves allergy symptoms. Hay fever is a condition that it is used to treat. Besides, is an antihistamine that helps with watery eyes, runny nose, itchy eyes/nose, sneezing, hives, and itching.The active ingredient in Zyrtec is cetirizine. Apart from this, our provided Cetirizine Dihydrochlorideworks by preventing your body from producing a natural molecule called histamine during an allergic reaction. It is used to treat long-term allergy symptoms.