The effectiveness of MFC (mitomycin C, 5-fluorouracil and cytosine arabinoside) therapy for nonresectable cancers and cancers recurring after surgery was investigated in 60 patients with solid cancers aged 26 to 69 years. Treatment was effective in 28 patients (47%) including seven (12%) who showed a very good response. Side effects included anorexia, vomiting, melena, anemia, decreased leukocyte and platelet counts, and impaired renal function. In particular, hemorrhage of the digestive tract should be watched carefully during MFC therapy. MFC therapy is suitable for solid tumors of the breast and digestive organs, especially with metastases to the lymph nodes. Response to treatment is generally seen after 6--10 doses. If there is no response at this time, treatment should be changed. In cases where induction of remission is successful, maintenance therapy should be continued keeping the frequency of administration to a minimum. Remission is readily induced with MFC therapy, but because of the problems of hemorrhage of the digestive tract, and bone marrow suppression, its use for outpatient treatment is not considered safe. Therefore, alternative treatment should be given for long term maintenance of remission. FAMT (5-fluorouracil, cyclophosphamide-endoxan, mitomycin C, chromomycin A3 -toyomycin) therapy is considered safe and suitable for maintenance therapy in outpatients. Three cases in which MFC therapy was very effective are described to illustrate the treatment program.