Fifty-two women with advanced breast cancer were treated with 6 cycles of epirubicin. Even though the study was started with a dose schedule of 110 mg/m2 every 3 weeks, the average treatment interval was 26 days and the median weekly dose 78% of the protocol requirement. Forty-eight patients were evaluable for response; 3 achieved a complete remission which lasted for 17, 24 and 65 weeks, respectively, and 14 a partial remission. Median survival was 32 weeks. Toxicity included nausea/vomiting (68%), anemia (24%), leukopenia (37%), thrombocytopenia (8%), alopecia (81%), stomatitis (24%), diarrhea (14%), fever (19%) and fatigue (14%). Also 1 treatment-related death occurred and 2 cases of arrhythmia. Monotherapy with high doses of epirubicin has definite activity in advanced breast cancer and deserves further study in combination with hematopoietic growth factors which might allow a higher dose intensity.