Bromocriptine1, a lysergic acid derivative with a bromine atom at position 2, has been found to have unique effects on the dopamine receptors in the pituitary and central nervous system and peripherally. It is rapidly and completely absorbed from the gut and is mainly excreted in the bile and faeces. It seems to have a particular specificity for the pituitary prolactinotrophe although it does have other effects in different disease states. In spite of the fact that it is an ergot derivative, it is remarkably free of ergot vascular side effects in the doses needed for therapeutic benefit. The most common adverse effects are nausea, vomiting and postural symptoms. These can be overcome by starting at low doses and increasing to therapeutic levels. Its major use is in the suppression of prolactin in states where this hormone is elevated irrespective of cause. It has also been used in the treatment of acromegaly and is under investigation for use in other disease states probably linked with the prolactin system or dopaminergic receptors.