Many antipsychotic medications have the potential to raise prolactin levels leading to a range of negative consequences. In addition to symptoms such as gynaecomastia, galactorrhoea, menstrual irregularities and sexual dysfunction it is becoming clear that there are a number of important and potentially serious long-term consequences, including a loss of bone mineral density and a possible association with the development of breast cancer. It is clear, therefore, that the tendency to raise prolactin should be an important consideration in the use of antipsychotics but, to a large degree, this area has been neglected in clinical practice and research when compared with other potential adverse effects. We consider some of the practical clinical issues in prolactin measurement and the management of high results. We will identify the areas of uncertainty that remain for clinicians and consider the practical questions that future research should address.