Epirubicin is an agent with a lower incidence of cardiotoxicity and myelotoxicity compared with doxorubicin; and it is active in patients with non-Hodgkin's lymphoma (NHL). Our aim was to define the therapeutic efficacy and toxicity of dose-intensified epirubicin in combination With cyclophosphamide, vincristine, and prednisone (CEOP) in patients with diffuse large-cell NHL. Previously untreated patients aged between 15 and 75 years, with at least one measurable lesion, adequate liver, renal, cardiac functions, and no central nervous system involvement were included in the study. The planned chemotherapy regimen CEOP consisted of cyclophosphamide 750 mg/m(2), epirubicin 100 mg/m2, and vincristine 1.4 mg/m(2) intravenously on day I and 100 mg prednisone taken orally on days I to 5. Courses were repeated every 21 days. Patients With stage I and H received four cycles of chemotherapy followed by involved-field radiotherapy, and patients With stage III and IV received six cycles of chemotherapy followed by radiotherapy to bulky lymph node sites. Seventy-five patients were enrolled in the study. The complete response rate was 83.8%, and 72 patients were assessable for toxicity. The most common toxicity was myelosuppression; 13.9% of the patients had grade III-IV neutropenia. Severe mucositis, diarrhea, and emesis were uncommon (<10%). At a median follow-up period of 41 months, the 5-year progression-free survival and overall survival rates were 63.5% and 65.3%, respectively. Increasing the dose intensity of epirubicin can yield a similar complete response rate compared With the regimens used in NHL Without significantly increasing the toxicity rate associated with chemotherapy. The role of dose-intensive epirubicin should be investigated further in future randomized trials.