Based on the propensity of fat emulsion to be absorbed mainly into lymphatic capillaries and regional lymph nodes, preoperative oral administration of 5-FU emulsion was attempted as an adjuvant chemotherapy to surgery for gastric carcinoma. In our previous studies, it was demonstrated that the mean 5-FU level in the regional lymph nodes was higher in patients who received the 5-FU solution. Since 1974, we have administered 5-FU emulsion preoperatively to 167 patients with gastric cancer (500 mg X 10 days) and examined histologically the effect of this regimen on the metastatic foci in the lymph nodes. A positive change, such as marked necrosis or marked degeneration, was found in 58% of the metastatic lesions. Sixty-four patients with advanced cancer who received the preoperative 5-FU emulsion also received a curative resection between 1974 to 1977 in addition to postoperative chemotherapy (MMC 40 mg and 5-FU more than 5000 mg) (Group A). Their survival rate was compared with that of the curatively operated advanced cancer patients from 1959 to 1973 who received the same postoperative chemotherapy only (Group B, N = 59) and with that of patients, from 1959 to 1970, who received no chemotherapy (Group C, N = 222). The 5 year survival rate of Group A was 0.53 +/- 0.07, which was higher than that (0.49 +/- 0.07) of Group B and that (0.40 +/- 0.10) of Group C. Comparing the 5-year survival rates of the 3 groups from several points of view, such as a stage of cancer progress absence of serosal invasion, the 5-year survival rate of group A was higher than that of other groups. Although these differences between Group A and B were not statistically significant, but those between Group A and B were significant. From these results it is suggested that preoperative oral 5-FU emulsion might be effective as an adjunct to surgery for gastric cancer.