Résumé : Doses of 10 or 20 mg cyclophosphamide/kg body weight were administered daily to mice for up to 20 days. This caused significant reductions in the incidence of prenatal (developing) follicles and significant increases in atretic (degenerating) follicles within the ovaries. Attempts to prevent cyclophosphamide-induced damage by simultaneous treatment with oestrogen alone, oestrogen plus progesterone, or danazol (a synthetic androgen) demonstrated that danazol effectively prevented the ovarian damage. The efficacy of danazol was considered to be due to its ability to inhibit LH/FSH secretion and, indirectly, the development of new ovarian follicles.