The Authors try out Nomifensine, a new antidepressant drug which activates dopaminergic neurotransmission by inhibiting the DA reuptake. The patients tested consisted of: 11 normoprolactinemic control patients; 2 hyperprolactinemic patients with sellar alterations; 5 hyperprolactinemic patients with no radiological alterations; 6 patients with micro-adenomas; 1 patient with macroadenoma. We administered 200 mg of the drug orally and then took blood samples for 4 hours. We conclude positively that nomifensine is a useful complement to the diagnostic collage for discriminating between tumorous and non-tumorous hyperprolactinemia, and we look forward to further research which will increase the literature on this subject and which will explain some mechanisms and effects which have not yet been clarified, and we hope that this research will further prove the importance of the test.