The main toxicity of Oxaliplatin, a major drug in the treatment of metastatic colorectal carcinoma, is neurologic. Severe sinusoidal lesions of the liver have been recently described in patients receiving pre-operative (neoadjuvant) oxaliplatin-containing chemotherapy, but their clinical relevance is unknown. Four patients with metastatic colon cancer receiving oxaliplatin, 5 fluorouracil and elvorin, developped a progressive increase in gammaglutamyl transpeptidase and alkaline phosphatase, contrasting with tumour regression established by CT-scan and decrease in serum carcinoembryonic antigen concentrations. Histological examination of liver biopsies showed sinusoidal dilatation in all cases, with perisinusoidal fibrosis and centrilobular vein lesions in 3, peliosis in 1 (in a patient receiving oxaliplatine by intraarterial hepatic route), and nodular regenerative hyperplasia in 1. The patient with peliosis developped ascites, and died from hepatic failure, despite withdrawal of the drug. The patient with nodular regenerative hyperplasia developped jaundice, ascites and severe infection following a right hepatectomy. In the three surviving patients, liver function tests improved after the withdrawal of oxaliplatin, and, in one, deteriorated again after reintroduction of the drug. The prevalence of liver sinusoid lesions induced by oxaliplatin-containing chemotherapeutic regimens is probably underestimated. Careful monitoring of gamma-glutamyl transpeptidase and alkaline phosphatase is mandatory in treated patients, especially in those receiving adjuvant therapy, in whom significant sequelae could occur despite initially asymptomatic lesions.