The medication known as Generic Allegra D is comprised of both a decongestant called pseudoephedrine and an antihistamine known as fexofenadine...

In each Allegra dosage you take, you consume an antihistamine known as fexofenadine Fexofenadine works in your body to block histamines which cause allergic reactions...

An allergy is a reaction by the body when the body ingests certain substances such as pollen and other triggers...