Cabergoline belongs to a group of drugs known as dopamine agonists. It is prescribed to treat a condition called hyperprolactinemia. This condition occurs as a result of too much prolactin, a natural substance produced by the body which helps women who are breast feeding to produce milk. However, excess levels of prolactin may cause fertility problems, missed periods and unwanted breast milk production. Male patients with too much prolactin may experience an enlargement of the breasts and a reduced libido. This drug works by reducing the amount of prolactin produced by the pituitary gland.