Continuous intravenous infusion (CVI) of 5-fluorouracil (5-FU) plus daily low-dose cisplatin (CDDP) was evaluated in 59 patients with advanced and unresectable colorectal carcinoma. The procedure consisted of 5-FU 320 mg/m2/day, CVI and CDDP 2.5-3.5 mg/m2/day, infused for one hour five times a week (low-dose FP therapy) was performed for at least four weeks. The rates of complete and partial response, along with side effects were studied. Also, the effect of low-dose FP therapy on the prognosis of patients with colorectal carcinoma was investigated. The rate of complete and partial response was 57.1%. The frequency of severe side effects (grade 3 and 4) was 10.5%, and no death from side effects was noted. The effect of low-dose FP therapy on the prognosis of advanced and unresectable colorectal carcinoma was studied. It is suggested that this chemotherapy might contribute to the survival of patients with colorectal carcinoma. We designed the chemotherapy of intermittent administration (day by day) of 5-FU 600 mg/m2/day and daily CDDP 2.5-3.5 mg/m2/day (intermittent FP) in order to decrease the rate of side effects and their severity. No cases with grade 3 or 4 side effects were experienced, but the response rate was mostly similar to that of low-dose FP therapy. We concluded that low-dose FP and intermittent FP therapy might be fairly effective for advanced and unresectable colorectal carcinoma.