Each allergy medicine tablet contains 10 mg Cetirizine HCl antihistamine to relieve your worst allergy symptoms, indoors and out, for a full 24 hours. ZYRTEC tablets help relieve seasonal allergy and other upper respiratory allergy symptoms, including itchy eyes, sneezing, runny nose, itchy nose or throat, and more. These allergy relief medicine tablets help treat symptoms of pollen allergies & other outdoor seasonal allergies, as well as indoor allergies, such as dust allergies, pet allergies, and more. From the #1 allergist recommended brand among OTC oral antihistamines, this prescription-strength allergy medicine starts working hard at hour 1 and works twice as hard when you take it again the next day.