Preliminary data suggesting synergistic activity of cisplatinum and doxorubicin and the expected poor prognosis of women with breast cancer who progress on treatment with cyclophosphamide, methotrexate and 5-fluorouracil (CMF), led to a trial of monthly doxorubicin (50 mg/M2), vincristine (1.4 mg/M2) and cisplatinum (50 mg/M2) in such patients. Overall partial response rate to this regimen was 42%; 37% progressed and 21% could not complete two cycles of therapy because of gastrointestinal (three or renal (one) toxicity. This study does not support the use of cisplatinum, 50 mg/M2, in combination with doxorubicin and vincristine in patients with breast cancer which has proven refractory to CMF therapy.