Cetirizine is An Antihistamine that Reduces the Natural Chemical Histamine in the Body. Histamine Can Produce Symptoms of Sneezing, Itching, Watery Eyes, and Running Nose. It is Used to Treat Cold. Cetirizine is also Used to Treat Itching and Swelling Caused By Hives. Cetirizine's Primary Indication is For hay Fever and other Allergies. Because the Symptoms of Itching and Redness in These Conditions are Caused By Histamine Acting On the H1 Receptor, Blocking Those Receptors Temporarily Relieves Those Symptoms. Cetirizine is also Commonly Prescribed to Treat Acute and (in Particular Cases) Chronic urticaria, More Efficiently Than Any other Second-generation Antihistamine. It is Preferred Over diphenhydramine in Many Countries Because, While Being as Effective as It for Treating Hives-related Skin Diseases, Cetirizine Does Not Affect the Regular Functioning of the Brain.