Background and aims: Supplementation of fish oil (FO) containing lipid emulsions has been associated with a reduction in the length of hospital stay, infections and liver dysfunction in patients undergoing major surgery. We carried out a meta-analysis and subgroup analysis to examine randomised clinical trial (RCT)-based evidence of the aforementioned effects. Methods: Four databases, reference lists and the WHO ICTRP were systematically searched for RCTs to access the clinical efficacy of fish oil-enriched total parenteral nutrition in post-surgery patients. Methodological quality assessment was based on the Cochrane Handbook and GRADE. Results: Twenty-one RCTs were enrolled for meta-analysis. FO was associated with a significant reduction in the length of hospital stay (mean = -2.14 d, 95% CI = -3.02 to -1.27), infections (OR = 0.53, 95% CI = 0.35-0.81), ALT (mean = -6.35 U/L, 95% CI = -11.75 to -0.94), GGT (mean = -11.01 U/L, 95% CI = -20.77 to -1.25) and total bilirubin (mean = -2.06 μmol/L, 95% CI = -3.6 to -0.52), as well as a non-significant change in mortality and postoperative medical cost. The quality of evidence of each clinical outcome was accessed as high. Conclusion: FO-enriched lipid emulsions are likely to reduce infections, the length of hospital stay and liver dysfunction without influencing mortality and may be a safe and preferable choice in post-surgery patients. Further well-designed trials should be performed to determine whether FO lipid emulsions reduce mortality in patients undergoing hepatic surgery, especially liver transplantation, and the cost effectiveness of such treatment.