The purposes of this administration were to inactivate cancer cells liberated from the primary tumor, to prevent them from metastasizing to other organs and to treat established metastatic cancer. Sixty-one patients with advanced gastric cancer who had received preoperative 5-FU dry syrup administration and who had also undergone curative resection between 1976 and 1982, in addition to postoperative chemotherapy (more than 20 mg MMC, 5,000 mg 5-FU), (Group A) were admitted to the present study. Their survival rate was compared with that of 67 patients given curative resection for advanced cancer without preoperative 5-FU dry syrup, who received the same postoperative chemotherapy only (Group B) during the same period. The 5-year survival rate for Group A was 0.55 +/- 0.06, higher than the rate of 0.42 +/- 0.06 for Group B. Comparing the 5-year survival rates of both groups in terms of clinicopathological factors such as stage of cancer progression, serosal invasion, lymph node metastasis, and lymphangitic and blood vessel invasion, the 5-year survival rates for Group A were higher than those for Group B. There were significant differences for histological stage III and blood vessel invasion between the two groups. From these results, it is suggested that preoperative oral 5-FU dry syrup might be effective as an adjuvant therapy to surgery for gastric cancer.