Hyperprolactinaemia is a relatively common endocrine abnormality caused by an increased secretion of prolactin from the pituitary gland. There are many causes of hyperprolactinaemia; drug therapy is a common cause in clinical practice. The present pharmacoepidemiological study conducted an analysis of the French Pharmacovigilance Database from January 1, 1985, to December 2000. We investigated the rates of hyperprolactinaemia according to therapeutic drug class, particularly where the Summaries of Product Characteristics (SPC) did not mention hyperprolactinaemia, and estimated the risk of developing hyperprolactinaemia during treatment. We calculated the odds ratio (OR) of reports associated with hyperprolactinaemia for all drugs. Of the 182,836 spontaneous adverse drug reactions reported to the French Pharmacovigilance network, 159 were hyperprolactinaemia. The sex ratio was 5.9 (136 women and 29 men), and mean age was 40 (range 14-85) years. Of the total number of adverse reactions, 31% were associated with neuroleptics, 28% with neuroleptic-like drugs, 26% with antidepressants, 5% with H2-receptor antagonists, and 10% with other drugs. Neuroleptics are not the only class of drugs for which hyperprolactinaemia is reported. Some drugs are clearly associated with an increased risk of hyperprolactinaemia, particularly the following: veralipride (OR = 108.7; IC 95%: 51.82-228), indoramin (OR = 78.68; IC 95%: 33.93-182.48), sertraline (OR = 15.74; IC 95%: 5.80-42.75), and ranitidine (OR = 4.43; IC 95%: 1.82-10.81). All these drugs are reported in the literature as inducing hyperprolactinaemia, although this adverse effect is not mentioned in the SPC. It is thus necessary to harmonise the SPC and encourage health professionals to notify all adverse reactions to their pharmacovigilance centres.