Currently, randomized phase III trials have demonstrated that docetaxel is an effective strategy in the adjuvant treatment of breast cancer. However, previous attempts to incorporate docetaxel with an anthracycline in a dose-dense regimen have been unsuccessful. Therefore, new schedules containing both drugs should be explored. Forty-four patients with high-risk operable breast cancer entered this feasibility study. They were treated with three cycles of epirubicin 110 mg/m2 every 2 wk with G-CSF followed by three cycles of "intensified" CMF (840 mg/m2 cyclophosphamide; 57 mg/m2 methotrexate; 840 mg/m2 fluorouracil) every 2 wk with G-CSF followed 3 wk later by nine weekly cycles of 35 mg/m2 docetaxel (E-CMF-doc). Totally, 39 patients (89%) received all cycles of chemotherapy. The vast majority (92%) of cycles were administered at full dose. Therefore, dose intensity was sufficiently maintained for all drugs. Toxicity was generally mild to moderate. Most frequently recorded side effects apart from alopecia were neutropenia (54%) and nausea/vomiting (89%). Infection developed in nine patients. Two cases of febrile neutropenia were reported. The E-CMF-doc regimen, as used in this study, is feasible and well tolerated. Its impact on survival should be evaluated in phase III trials.