Benadryl Allergy One A Day 10mg Long-Lasting Hayfever Relief 30 TabletBENADRYL® Allergy One A Day 10 mg Tablets offer daily relief from the symptoms of hay fever and other allergic conditions such as pet, skin and dust allergies. BENADRYL One A Day 10 mg Tablets contain 10 mg cetirizine dihydrochloride which is an antihistamine that helps releive allergy symptoms such as sneezing, runny nose and watery eyes. It can also be used to treat allergic skin reactions. These include uticaria, also known as hives, where the skin looks blotchy, with white raised wheals (bumps) surrounded by redness.