Hydroxyzine Products | Cleanchem - Hydroxyzine is an antihistamine used to treat anxiety, nausea, allergies, and sleep disorders. It is also used as a sedative before or after surgery. Hydroxyzine works by blocking histamine receptors in the body, which helps to reduce symptoms such as itching, sneezing, and runny nose. It also has calming effects, which make it useful in treating anxiety and insomnia.