Prolactin is known as the breast milk hormone. When it occurs naturally and normally, it stimulates milk production in pregnant women. However if prolactin levels are too high in women who are not pregnant, it can lead to irregular or no ovulation.

Parlodel is used to control (and lower) prolactin levels by stimulating dopamine receptors. Once prolactin levels normalize, regular ovulation often begins. Major side effects may include nausea, vomiting, and dizziness.