Allegra tablet is a brand name for fexofenadine, which is an antihistamine medication used to treat and prevent allergy symptoms such as red, itchy eyes, sneezing, a runny or stuffy nose, or hives. It works by blocking histamine, a substance released by the body during an allergic reaction. Allegra tablet is also used to treat skin itching and hives caused by a condition called chronic idiopathic urticaria in adults and children. If you are taking the over-the-counter product to self-treat, read all directions on the product package before taking this medication. If you have any questions, consult your pharmacist. If your doctor has prescribed this medication, take it as directed with or without food, usually once daily.