The use of long acting gonadotropin-releasing hormone (Gn-RH) agonist produces a reversible hypogonadotropic hypogonadism. This effect has been used as presurgical treatment of uterine myomata, resulting in amenorrhea and reduction in uterus and tumour sizes. We describe the case of a 43 year old patient, having a uterine myoma associated with metrorrhagia, admitted to hospital because of extensive deep phlebothrombosis requiring urgent anticoagulation. Because of the risk of exacerbating metrorrhagia and considering the high morbidity associated to emergency hysterectomy, we decided medical treatment with a depot GnRH agonist (leuprolide acetate 3.75 mg IM monthly). Bleeding ceased within 3 days, allowing the maintenance of anticoagulant treatment. A marked reduction in uterine size postponed total hysterectomy to 3 months later. The characteristics of GnRH analogues, their action mechanisms, adverse effects and other clinical indications are discussed.