Xantremine, also known as cetirizine hydrochloride, is a second-generation antihistamine H1 receptor antagonist with a fast onset of action and good efficacy after oral administration. It generally does not cross the brain barrier, so it has weak sedative effects and few side effects. Cetirizine hydrochloride is mainly used for the rapid relief of symptoms associated with allergic rhinitis, such as sneezing, nasal itching, and nasal mucosal congestion caused by allergic rhinitis. It can be used to treat itchy eyes, tearing and congestion caused by allergic conjunctivitis, and to relieve the symptoms of chronic urticaria, such as itchy skin and wind clumps. Also cetirizine hydrochloride is used to treat itchy skin caused by non-allergic diseases, such as psoriasis vulgaris, neurodermatitis, seborrheic dermatitis, etc.