A prospective study with two cytotoxic combinations (cyclophosphamide, methotrexate, and fluorouracil (CMF), and adriamycin plus vincristine (AV)) was carried out in 110 patients with advanced breast cancer. There was no significant difference between the treatment groups in the response rate after primary treatment, the median duration of response, and the median survival. In both groups responders survived for longer than non-responders. Secondary treatment after crossover for progression or relapse resulted in response rates of 35% for AV and 20% for CMF. Toxicity was mainly represented by reversible haemosuppression. These results are comparable with those obtained with other multiple-drug regimens, and combination chemotherapy alone seems to have reached a plateau in its capacity to control disseminated breast cancer.