Adjuvant chemotherapy consisting of 5-fluorouracil and semustine was given to 26 patients who had undergone resection (with curative intent) of hepatic metastatic lesions from a primary colorectal carcinoma. Our objective was to obtain preliminary observations regarding the effectiveness of this regimen for improving the long-term survival associated with hepatic resection alone in these patients (the overall 5-year survival after hepatic resection is 25% at our institution). At the time of analysis, the malignant disease had progressed in 19 of our patients, and 17 patients had died. For all patients who receive adjuvant chemotherapy, the median duration of survival is 34 months, and the estimated 5-year survival is 15%. Statistical analysis indicated no significant advantage in survival for the study patients in comparison with 26 control patients who were treated with hepatic resection only and were closely matched for prognostic factors. Because 5-fluorouracil plus semustine conferred no apparent beneficial effects as an adjuvant treatment in this exploratory study, we do not recommend a definitive randomized trial of this regimen.