The majority of patients who underwent surgery for colorectal liver metastases have been previously treated with 5-FU either as adjuvant chemotherapy or as a primary treatment. We have performed a retrospective study to assess whether this chemotherapy increases the risk of liver resection. Mortality, morbidity and histology of the resected liver of two groups of patients having colorectal liver metastases who underwent major resection were studied. The first group included 17 patients who had received at least 2 courses of 5-FU chemotherapy within 3 months prior to liver resection. The second group included 18 patients who had received no chemotherapy and who were used as controls. Perioperative mortality was nil. Intraoperative blood loss during liver resection (1 +/- 2.5 vs. 1.2 +/- 2 units) was similar in the two groups. Changes of liver function tests on days 2 and 5 were similar in the two groups. Morbidity rate was similar in the two groups (29 vs. 22%) with a mean duration of postoperative hospital stay of 19 +/- 9 days in the 5-FU group and 16 +/- 6 days in the control group. Although 7 (41%) patients in the 5-FU group had an abnormal parenchyma consistency as compared to only 3 (17%) in the control group, the pathological findings within the resected specimen were not different. 5-FU based systemic chemotherapy does not increase the risk of liver resections.