While both endocrine therapy and chemotherapy are of proven value in the treatment of advanced breast cancer, the effects of combining these two methods or applying them consecutively have been relatively disappointing. This may be due to endocrine therapy suppressing cell division, in hormone-dependent tumors, whereas chemotherapy acts mainly on active-dividing cells. A trial protocol has therefore been devised which seeks to exploit the properties of both types of therapy. Oestrogen suppression is first obtained by aminoglutethimide (Orimeten) plus hydrocortisone; after 2 weeks, ethinyloestradiol is given to induce cell division and followed 24 h later by a combination of 3 cytotoxic agents given intravenously. This pattern of therapy, repeated at regular intervals, appears to be producing favorable clinical results. A phase-III study is being started among patients with hormone-dependent advanced breast cancer.