The clinical effects of chemoimmunotherapy including levamisole on advanced gastrointestinal cancer were evaluated. A total of 81 patients with histologically proved advanced gastrointestinal cancer including 67 cases of stomach carcinoma entered in this study. They were divided randomly into the control group on the two-drug regimen of 5-FU (250 mg/body/day, i.v. daily) and adriamycin (20 mg/m2/day, i.v. on days 1 and 2, q. 3 wks.) and the levamisole group on the three-drug regimen of above two drugs plus levamisole (150 mg/body/day, p.o. on days 5, 6 and 7, q. 2 wks.). Forty cases were allocated to the control group, and 41 cases to the levamisole group. No significant difference was observed in terms of a response rate between these two groups, though the response rate was slightly higher in the levamisole group (21.7%) than in the control group (10.5%). The median duration of response was 119 days in the levamisole group and 77 days in the control group. Therefore, it indicated that longer duration of response was obtained by using chemoimmunotherapy including levamisole compared to chemotherapy alone. The 50% survival time was significantly prolonged in the levamisole group (199 days) compared with the control group (118 days). Incidence of nausea and vomiting among the side effects by the regimens was significantly higher in cases on a three-drug regimen than those on a two-drug regimen. The results obtained in the present studies suggest that levamisole in combination with anticancer agents prolong the duration of response and the survival of the patients with advanced gastrointestinal or stomach carcinoma.