Exposure to pollen can cause your body to produce allergic symptoms, called hay fever. Cells in the linings of your nose and eyes release a chemical called histamine when they come into contact with pollen. Histamine causes inflammation (rhinitis), which produces symptoms such as sneezing and a runny or blocked nose. It also causes red, watery and itchy eyes (allergic conjunctivitis). Fexofenadine, an antihistamine, stops the effects of histamine and this helps to relieve these symptoms.
This is a companion discussion topic for the original article at https://patient.info/medicine/fexofenadine-tablets-telfast-allevia-allegra