Recently, high-dose FEC (fluorouracil, epirubicin, and cyclophosphamide) has been increasingly used in adjuvant chemotherapy for breast cancer in Japan. However, the safety and tolerability of high-dose FEC are not well evaluated in Japanese breast cancer patients. We studied the feasibility of FEC (75) (fluorouracil: 500 mg/m(2), epirubicin: 75 mg/m(2), and cyclophosphamide:500 mg/m(2), q 3 w, 6 cycles) as adjuvant chemotherapy for 59 primary breast cancer patients. Out of these patients, 56 (94.9%) finished 6 cycles-FEC. The mean epirubicin dose received was 431.7 mg/m(2) (95.9% of the intended dose of 450 mg/m(2)). Forty-five (76.2%) of 59 patients experienced neutropenia of grade 3 or 4, while the rates of febrile neutropenia (grade 3) and infection (grade 2) were 3.4% and 10.2%, respectively. Anemia (88.2%), fatigue (42.4%), nausea (40.6%), liver dysfunction (40.7%), and vomiting (18.7%) occurred, however most of them were mild and categorized into grade 1 or 2. No patients developed any cardiac failure symptoms. This study shows FEC (75) is well tolerable as adjuvant chemotherapy for Japanese breast cancer patients.