Bromocriptine (Parlodel) is used to treat symptoms of hyperprolactinemia (high levels of a natural substance called prolactin in the body) including lack of menstrual periods, discharge from the nipples, infertility (difficulty becoming pregnant) and hypogonadism (low levels of certain natural substances needed for normal development and sexual function). Bromocriptine (Parlodel) may be used to treat hyperprolactinemia caused by certain types of tumors that produce prolactin, and may shrink these tumors. Bromocriptine (Parlodel) is also used alone or with other treatments to treat acromegaly (condition in which there is too much growth hormone in the body) and Parkinson's disease (PD; a disorder of the nervous system that causes difficulties with movement, muscle control, and balance). Bromocriptine (Cycloset) is used with a diet and exercise program and sometimes with other medications to control blood sugar levels in people with type 2 diabetes (condition in which the body does not use insulin normally and therefore cannot control the amount of sugar in the blood). Bromocriptine (Cycloset) is not used to treat type 1 diabetes (condition in which the body does not produce insulin and therefore cannot control the amount of sugar in the blood) or diabetic ketoacidosis (a serious condition that may develop if high blood sugar is not treated). Bromocriptine is in a class of medications called dopamine receptor agonists. It treats hyperprolactinemia by decreasing the amount of prolactin in the body. It treats acromegaly by decreasing the amount of growth hormone in the body. It treats Parkinson's disease by stimulating the nerves that control movement. The way bromocriptine works to treat diabetes is not known.