To compare, in terms of compliance, toxicity, quality of life (QOL) and efficacy, intravenous 5-fluorouracil plus folinic acid with oral tegafur-uracil plus folinic acid as postoperative adjuvant chemotherapy after curative resection in patients with Dukes' stage B2 and C2 colon cancer. Among all patients with adenocarcinoma of the colon operated on between July 1997 and June 1999, 122 with Dukes' stage B2 or C2 colon cancer were enrolled in this study. Fifty-three patients were treated with intravenous 5-fluorouracil plus folinic acid (5-FU group) and 69 with oral tegafur-uracil plus folinic acid (UFT group). Compliance, toxicity, QOL and efficacy were evaluated. Compared with the 5-FU group, patients in the UFT group experienced a lower incidence of grade 1 toxicity. The incidences of grade 2-4 toxicity were similar in the two treatment groups. However, severe toxicity (grade 3 or 4) was rare in both groups. A steady and significant increase of the QOL score, both during and after therapy, was evident in both groups suggesting that chemotherapy is quite tolerable and does not deteriorate the patients' QOL. At the median follow-up duration of 28 months, the survival rate and disease free survival rate for the UFT and 5-FU groups were 94.9% vs. 92.5% and 87.5% vs. 84.1%, respectively (p > 0.05). These data suggest that oral tegafur-uracil modulated with oral folinic acid as an adjuvant chemotherapy in patients with Dukes' stage B2 and C2 colon cancer may be a good alternative to infusional 5- fluorouracil.