Vasopressin helps prevent the loss of water from the body by reducing urine output and helping the kidneys reabsorb water in the body. Vasopressin also raises blood pressure by constricting (narrowing) blood vessels.

Vasopressin is used to treat diabetes insipidus, which is caused by a lack of this naturally occurring pituitary hormone in the body. Vasopressin is also used to treat or prevent certain conditions of the stomach after surgery or during abdominal x-rays