A prospective randomized study involving gastric cancer patients was conducted to evaluate combined adjuvant chemotherapy. Forty-two patients under 80 years of age who underwent a curative resection of pathologic stage II or III gastric cancer were randomly assigned to receive adjuvant chemotherapy containing the following two regimens from 1993 to 1996. A) Oral 5'-deoxy-5-fluorouridin (5'-DFUR) plus cisplatin: 5'-DFUR, daily administration, combined with CDDP 15 mg/m2/day, 30-min drip infusion, fortnightly for 8 weeks, repeated every 16 weeks. B) Oral 5'-DFUR alone: 5'-DFUR, daily administration. The dosages of 5'-DFUR were assigned according to the patients' body surface area (BSA): BSA < 1.7 m2, 600 mg and BSA > or = 1.7 m2, 800 mg, daily administration, bid. Twenty patients were assigned to regimen A, and 22 to regimen B. All clinicopathological factors were equally distributed in each regimen. No adverse reactions greater than grade 3 occurred in either regimen. There was no significant difference between the two regimens in overall survival or overall disease-free survival. For patients with positive nodes, the 5-year disease-free survival rates were 56.4% in A and 38.3% in B (p = 0.29). In stage III patients, the 5-year disease-free survival rates were 55.6% in A and 20.7% in B (p = 0.26). No significant survival benefit was observed with the combined chemotherapeutic regimen, 5'-DFUR plus cisplatin, compared with 5'-DFUR alone.