From 1991 to 1997, we have treated 78 newly diagnosed patients with aggressive non-Hodgkin's lymphoma with a modified CHOP regimen in which epirubicin (60 mg/m2) was used in place of doxorubicin (50 mg/m2), i.e. CEOP (cyclophosphamide, epirubicin, vincristine and prednisolone). The median age was 41 years (range: 17 to 67). Sixty-four (82 per cent) had diffuse large cell (Working Formulation category G) histology. The median LDH level was 453 u/l. Thirty-three (42.3 per cent) and 45 (57.7 per cent) had stage I/II and stage III/IV disease, respectively. Fifty-five of 78 (71 per cent) CEOP-treated patients achieved CR, and the projected DFS and OS were both 65 per cent. In an earlier cohort of patients (from 1985-1991) treated with second or third-generation chemotherapy regimens (m-BACOD, MACOP-B, ProMACE-CytaBOM), CR was achieved in 95/123 (77 per cent) patients and the projected DFS and OS were 62 per cent and 55 per cent. There was no significant difference in the clinical characteristics, CR rates (p = 0.26), DFS (p = 0.38) or OS (p = 0.68) between patients who received CEOP or second/third-generation chemotherapy regimens. Of the patients treated with CEOP, 37.9 per cent, 28.8 per cent, 24.2 per cent and 9.1 per cent were in the age-adjusted International Index L, LI, HI and H risk groups, with CR rates of 82 per cent and 57 per cent in the L/LI and HI/H risk groups (p = 0.03). Moreover, patients in the L, LI and HI/H risk groups had significantly different projected DFS (87 per cent, 62 per cent and 39 per cent, p = 0.02) and OS (85 per cent, 80 per cent and 36 per cent, p = 0.006). In conclusion, CEOP is an effective regimen and the age-adjusted International Index is valid for Chinese patients with aggressive NHL.