Fexofenadine is used to relieve the allergy symptoms of seasonal allergic rhinitis ('hay fever'), including runny nose; sneezing; red, itchy, or watery eyes; or itching of the nose, throat, or roof of the mouth. Fexofenadine is in a class of medications called antihistamines. It works by blocking the effects of histamine, a substance in the body that causes allergy symptoms.