Thirty patients with measurable metastatic breast carcinoma were treated with a combination of cyclophosphamide 600 mg/m2 on day 1, levofolinic acid 100 mg/m2 plus 5-fluorouracil 375 mg/m2 on days 1-3, and epidoxorubicin (EDXR) in three refracted doses on days 1-3 with G-CSF rescue for 10 days. In the phase I part of the study, groups of 3 patients received EDXR 20, 25, 30, 35, and 40 mg/m2/day until the dose limiting toxicity (DLT) was reached. At the dose of 40 mg/m2/day prolonged grade 4 leukopenia, severe proctitis, and grade 3 diarrhea represented the DLT. All subsequent patients were treated at the maximal tolerated dose of EDXR (35 mg/m2/day). In the group of 18 patients treated at 35 mg/m2/day the overall response rate was 78%, with 22% CR and 56% PR. Four patients did not respond. Objective responses were seen at all tumor sites including bone and viscera, which usually are rather chemotherapy insensitive. Toxicity was generally acceptable. Although the response rate was quite high, the duration of objective tumor regression and patients' survival were not impressive. In conclusion, we do not recommend routine use of such an aggressive regimen for palliation of advanced breast cancer. Results of the present and similar studies may, however, be useful for planning of neoadjuvant or adjuvant trials with curative intent.