A new form of Metrodin (highly purified) characterized by the absence of any urinary protein contaminants and by a high specific activity, has been recently obtained through additional immunoextraction and chromatographic procedures. The respect of its main physico-chemical characteristics and the very low LH activity justify that the pharmacokinetics and the clinical efficacy of this new form are identical to those of the classical Metrodin. In a clinical point of view, Metrodin HP combines the double advantage of an excellent local and general tolerance (without any allergic side effect) and of a subcutaneous route of injection which allows a self-administration by the patient.