BACKGROUND Primary liver tumours and liver metastases from colorectal carcinoma are the two most common malignant tumours to affect the liver. The liver is second only to the lymph nodes as the most common site for metastatic disease. More than half of the patients with metastatic liver disease will die from metastatic complications. Percutaneous ethanol injection (PEI) causes dehydration and necrosis of tumour cells accompanied by small vessel thrombosis, leading to tumour ischaemia and destruction. OBJECTIVE To study the beneficial and harmful effects of percutaneous ethanol injection compared with no intervention, other ablation methods, or systemic treatments in patients with liver metastases. METHODS We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, LILACS, and CINAHL up to December 2012. METHODS We included all randomised clinical trials assessing the beneficial and harmful effects of percutaneous ethanol injection versus no intervention, other ablation methods, or systemic treatments in patients with liver metastases. METHODS We extracted the relevant information on participant characteristics, interventions, study outcome measures, and data on the outcome measures for our review, as well as information on the design and methodology of the studies. Quality assessment of the trials fulfilling the inclusion criteria and data extraction from the trials retrieved for final evaluation were done by one author and checked by a second author. RESULTS One randomised clinical trial was included, comparing transcatheter arterial chemoembolisation (TACE) + percutaneous intratumour ethanol injection (PEI) versus TACE alone. Forty-eight patients with liver metastases were included; 25 received the intervention with PEI and 23 received TACE alone.Mortality data were not reported. The trial reported the survival data after one, two, and three years. In the TACE + PEI group, 92%, 80%, and 64% of the patients survived after 1, 2, and 3 years respectively; in the TACE group, 78.3%, 65.2%, and 47.8% of the patients survived after 1, 2, and 3 years respectively. The hazard ratio was 0.57 (95% CI 0.19 to 1.67). The local recurrence was 16% in the TACE + PEI group and 39.1% in the TACE group, resulting in a relative risk (RR) of 0.41 (95% CI 0.15 to 1.07). Forty-five tumours (66.2%) out of 68 tumours in total shrunk by at least 25% in the TACE + PEI group versus 31 tumours (48.4%) out of 64 tumours in total in the TACE group (RR 2.08; 95% CI 1.03 to 4.2). The authors reported some adverse events, but with very few details. CONCLUSIONS On the basis of one small randomised trial, it can be concluded that addition of PEI to TACE, as compared with TACE alone, in patients with liver metastases seems to bring no clear benefit in terms of survival and local recurrence. The size of the tumour necrosis was larger in the combined treatment group. No intervention-related mortality or major complications were reported. More trials are needed.