ObjectiveTo systematically evaluate short-term efficacy of omega-3(ω-3) polyunsaturated fatty acidsupplemented parenteral nutrition in postoperative gastrointestinal malignancy. MethodsThe literatures published randomized control trials (RCT) were searched in PubMed, Embase, Scopus, Cochrane Library, CNKI, Weipu, and Wanfang Databases. The immune efficacy outcomes ofω-3 polyunsaturated fatty acid-supplemented parenteral nutrition in patients with gastrointestinal malignancy were compared. All the relevant studies were screened and the data were extracted before January 2015. The quality of included literatures was assessed by the risk of bias table provided on Cochrane Library. Statistical analysis was performed by Revman 5.3 software. ResultsSixteen RCTs involving 1019 patients (511 in the study group, 508 in the control group) were enrolled into the analysis. The results of meta analysis:①In the cell immunity:The proportions of CD3, CD4, CD4/CD8 in the study group were significantly higher than those in the control group[CD3:WMD=6.09, 95% CI (2.40, 9.77), P=0.001; CD4:WMD=5.25, 95% CI (3.30, 7.20), P < 0.00001; CD4/CD8:WMD=0.40, 95% CI (0.22, 0.58), P < 0.0001].②In the humoral immunity:The levels of IgA and IgG in the study group were significantly higher than those in the control group[IgA:WMD=0.56, 95% CI (0.36, 0.77), P < 0.00001; IgG:WMD=2.88, 95% CI (0.63, 5.13), P=0.01].③The count of lymphocyte in the study group was significantly higher than that in the control group[WMD=0.27, 95% CI (0.10, 0.43), P=0.002].④In the cytokines:The levels of interleukin-6 and tumor necrosis factor (TNF)-αin the study group were significantly lower than those in the control group[interleukin-6:WMD=-16.75, 95% CI (-25.00, -8.50), P < 0.0001; TNF-α:WMD=-6.25, 95% CI (-10.55, -1.95), P=0.004].⑤The rate of postoperative infective complications in the study group was significantly lower than that in the control group[OR=0.36, 95% CI (0.20, 0.66), P=0.0008]. ConclusionFor postoperative patients with gastrointestinal malignancy, ω-3 polyunsaturated fatty acid-supplemented parenteral nutrition could improve immune function, decrease postoperative inflammatory reaction, and reduce rate of infective complications.