End-point results of a 4-yr followup survey and a randomized control trial of lentinan (LNT) on patients with advanced or recurrent stomach cancer have been investigated in order to evaluate the clinical efficacy of LNT in combination with chemotherapeutic agent tegafur (FT). Eligible (68) patients in control groups were administered with FT consecutively at doses of 600 mg/day, and eligible (96) patients in the treated group were administered LNT in combination with FT. LNT was injected intravenously 2 mg weekly. Remarkable lifespan prolongation effects of LNT have been observed both at the end of the control trial and at the end of the followup survey (p less than 0.01) using Kaplan-Meier's method and the generalized Wilcoxian test. Remarkable survival at 1, 2 and 3 years has been observed in the treated group using lifetable analysis. Side effects of LNT have been transitional and not serious. Thus, LNT should be effective in combination with FT for patients with stomach cancer.