The effectiveness of combination chemotherapy with mitomycin-C (MMC) plus Futraful (N1-(2'-tetrahydrofuryl)-5-fluorouracil) for gastric cancer was investigated in a prospective randomized and controlled study. Two thousand sixty-four Japanese patients in 297 hospitals were entered, and 1805 could be followed. All patients had undergone gastrectomy from May 1975 to July 1976. These patients were grouped into two protocols: protocol I (intermittent intravenous injection of a moderate dose of MMC), and protocol II (bolus intravenous injection of MMC), each of which was allocated to group A (without Futraful) and group B (MMC plus oral administration of Futraful for 3 months). Statistically, this randomized study showed that the 5-year survival rate of patients with advanced cancer was not enhanced. However, with protocol II the Futraful administration seemed to improve the 5-year survival rate for those with Stage III cancer and for those with positive lymph node metastasis plus obvious serosal invasion.