Sixty-seven patients with measurable colorectal carcinoma were randomized to receive two different schedules of Methyl CCNU, 5-FU and Vincristine (MOF). The treatment schedule consisted of Methyl CCNU 150 mg/m2 po q 70 days, 5-FU 300 mg/m2 iv for 5 consecutive days q 35 days, and Vincristine 1 mg/m2 IV q 35 days. The same total dose was used in each arm; in MOF A, the Methyl CCNU was given on day 1, while in MOF B, the Methyl CCNU was divided and given over 5 consecutive days. In MOF A, there was a 10% partial response rate and a 10% minor response rate. In MOF B, the partial response rate was 12% and the minor response rate was 21%. This difference is not statistically significant, but the patients in MOF B experienced less gastrointestinal toxicity (p less than .001).