We retrospectively analyzed the efficacy and safety of aprepitant in breast cancer patients who were treated with FEC(5- fluorouracil, epirubicin, cyclophosphamide)or EC(epirubicin, cyclophosphamide). We divided patients into two groups according to the aprepitant approval period. The rate of severe nausea(@Grade 2)was significantly less in patients with aprepitant(acute 10. 0%, delayed 15. 0%)than those without aprepitant(acute 29. 1%, delayed 30. 9%). Complete response( no vomiting and no use of rescue therapy)in the acute phase was significantly higher in the aprepitant pretreated group than in the no aprepitant group(82. 5% vs 61. 8%, respectively). Moreover, complete response in the delayed phase was also higher in the aprepitant group than in the no aprepitant group(82. 5%vs 58. 2%, respectively). Pre-treatment with aprepitant did not increase adverse events including constipation and elevation of alanine transaminase. The aprepitant was effective in terms of prevention of chemotherapy-induced nausea and vomiting in patients treated with an anthracycline- based regimen.