目的  探讨添加omega-3 PUFAs 的营养治疗对消化系统恶性肿瘤患者术后感染并发症的影响。方法  检索 MEDLINE、EMBASE、Cochrane 对照试验中心数据库、中国知网和中国生物医学数据库，同时进行参考文献回溯。检索 起始时间为数据库默认时间，检索截止时间为2016年8月。检索主题词选择“omega-3 PUFAs”，“ omega-3 fatty acids”，“ fish oil”，“ gastrointestinal cancer”，“ digestive system neoplasms”，“ postoperative infection”，“ ω-3多不饱和脂肪酸”，“鱼油”， “消化系统恶性肿瘤”，“术后感染”。按照纳入与排除标准筛选出高质量随机对照试验。两组人员独立对研究方法详读综 合后进行数据提取，采用 RevMan 5.2 统计软件进行分析。结果  共检索到928 篇文献，最终共纳入 6 项高质量随机对照试 验，共 404 名患者，来自 4 个不同国家、不同种族。Meta 分析结果显示，添加 omega-3 PUFAs 组患者的总体感染并发症发 生率低于对照组，两组间差异存在统计学意义（OR=2.2，95%CI=1.05~4.61，P=0.037）。进一步对国别、omega-3 PUFAs 添加时间及营养治疗方式行亚组分析，由于纳入研究患者数量的限制，亚组分析未获得有意义的结果。结论  添加 omega-3 PUFAs 可能会降低消化系统恶性肿瘤患者术后感染并发症发生率。但是本研究异质性高（I2=54.7%，P=0.051），纳入研究 患者数量有限，亚组分析无法获得有意义的结论，需要大样本前瞻性临床试验验证 omega-3PUFAs 的作用。

Objective To systematically review the effect of omega-3 PUFAs supplementation on postoperative patients with gastrointestinal cancer. Methods Databases of MEDLINE, EMBASE, cochrance central register of controlled trials, CNKI and CBM had been searched. The start time of retrieval is the default database, the deadline of retrieval is August 2016. The search terms were omega-3 PUFAs, omega-3 fatty acids, fish oil, gastrointestinal cancer, digestive system neoplasms, postoperative infection. According to include and exclude standard screening high quality randomized controlled trials, two groups independently reviewed articles, extracted data and assessed the methodological quality. RevMan 5.2 was used for statistical analysis. Results 928 articles were retrieved, 6 high-quality randomized controlled trials with 404 patients, from 4 different countries and nationalities were included. Meta-analysis results showed that the incidence of infection in the ω-3PUFAs group was lower than that in the control group, and the difference was statistically significant (OR=2.2, 95%CI=1.05~4.61, P=0.037). Subgroup analysis on country, time of omega-3 PUFAs supplements intake and ways of nutritional support, for the limitation of the number of the patients, subgroup analysis was unable to draw any definitive results. Conclusions Supplement with omega-3 PUFAs may reduce the incidence of infection complications on postoperative patients with gastrointestinal cancer. However, there was a high heterogeneity (I2=54.7%, P=0.051). Because of limitation of the number of patients included in the study, subgroup analysis was unable to draw any definitive conclusions, large prospective clinical trials are needed for this topic.