BACKGROUND The purpose of this study was to determine the efficacy and toxicity of uracil/ftorafur (UFT) plus oral leucovorin (LV) as first-line chemotherapy for patients with metastatic colorectal cancer and salvage chemotherapy with weekly high-dose 5-fluorouracil (5-FU)/LV 24 h infusion. METHODS Adult patients with no prior chemotherapy for metastatic diseases were enrolled to receive oral UFT 300 mg/m(2)/d plus LV 90 mg/d for 28 days. Treatment was given continuously for 28 days followed by a 7 day rest period from all treatment. For UFT failed patients, weekly 24 h infusion of 5-FU 2600 mg/m(2) plus LV 100 mg/m(2) was used as salvage therapy. RESULTS Fifty-one patients with metastatic colorectal cancer were enrolled in the study. The objective response rate was 29.5% [95% confidence interval (CI), 16.8-45.2%] among the 44 evaluable patients and 25.5% in the intent-to-treat population. The median survival for all 51 patients was 16.6 months. The median time to progression was 5.9 months. Diarrhea was the major adverse effect of UFT/LV that made patients reduce dosage. Grade 3 or 4 diarrhea developed in 13.7% of patients. Twenty-six patients were treated with weekly 24 h infusional 5-FU/LV as salvage therapy and only two patients responded. CONCLUSIONS Our results suggest that this 28 day schedule of UFT/LV regimen may offer a well-tolerated, full oral treatment option with efficacy that appears comparable to that of intravenous 5-FU/LV regimens. Parenteral 5-FU/LV as salvage therapy for UFT refractory patients is not recommended.