Hydroxyzine reduces activity in the central nervous system. It also acts as an antihistamine that reduces the natural chemical histamine in the body. Histamine can produce symptoms of sneezing and runny nose, or hives on the skin. Hydroxyzine is used as a sedative to treat anxiety and tension. It is also used together with other medications given for anesthesia. Hydroxyzine may also be used to control nausea and vomiting. Hydroxyzine is also used to treat allergic skin reactions such as hives or contact dermatitis.