A new combination chemotherapy including mitoxantrone 10 mg/m2 i.v. on day 1 and 5-fluorouracil 400 mg/m2 i.v. plus folinic acid 200 mg/m2 i.v. on days 1-5 was administered every 28 days to 13 patients with locally advanced or metastatic colon (1 case), ractosigmoid colon (4 cases), or rectum (8 cases) carcinoma. The median number of cycles performed was 3 (range, 1-9). No patient achieved complete or partial remission with this regimen, whereas 5 showed a stable disease lasting 3-8 months. Acute toxicity was mild/moderate in intensity and comparable to that reported with the standard 5-fluorouracil + folinic acid combination. Since we observed no major responses in our 13 consecutive patients, we consider that the overall activity of our regimen, at the doses and schedule utilized, was only moderately effective in advanced colorectal carcinoma.