AIMS: Because of its efficacy, oxaliplatin (OX) is increasingly used as a chemotherapeutic agent in the treatment of colorectal liver metastases (CRLM). Oxaliplatin-associated liver toxicity has been reported and can affect clinical practice, but studies on its prevalence and a full pathological description are lacking. The aims of this study were to fill this gap by providing, from a pathologist's perspective, a detailed assessment of the spectrum of hepatic lesions associated with OX, to suggest a scoring system to quantify them, and to investigate the protective effect of bevacizumab against OX-associated damage. METHODS AND RESULTS: The spectrum of oxaliplatin-associated liver lesions was investigated in a multi-institutional series of surgically resected CRLM (n = 385). Among 274 patients treated by OX, 54% had moderate/severe sinusoidal obstruction syndrome (SOS). Peliosis, centrilobular perisinusoidal/venular fibrosis and nodular regenerative hyperplasia (NRH) developed in 10.6%, 47% and 24.5%, respectively. The 111 patients treated by surgery alone had no lesions. Hepatic lesions were less severe in patients treated with OX/bevacizumab (n = 70) compared with the group treated by OX alone (n = 204), with an incidence of moderate/severe SOS (31.4% versus 62.2%), peliosis (4.3% versus 14.6%), NRH (11.4% versus 28.9%, respectively) and centrilobular/venular fibrosis (31.4% versus 52%, respectively) (P < 0.001). CONCLUSIONS: Pathologists should be aware of the distinctive lesions associated with OX and of their high prevalence. OX-related lesions are less frequent in patients treated with bevacizumab, suggesting that this drug has a preventive effect. Uniform criteria for diagnosis and grading of OX-associated lesions should help to include histological data in the optimal multidisciplinary management of CRLM.