ive: Optimization of nutritional status could improve surgical outcomes.In patients without obvious nutrition risk,preoperative Omega-3 fish-oil oral nutrition supplement (ONS) is beneficial by mechanisms such as enhancing immune function and reducing systemic inflammatory responses.For locally advanced gastric cancer (AGC) patients undertaking preoperative chemotherapy,it has not been established if fish-oil supplement may decrease postoperative complications.All patients were taken gastrectomy with curative intent.Method: We studied 60 patients who were diagnosed as AGC they were divided into 2 groups and 56 of them could finish preoperative chemotherapy and undertaken curative gastrectomy.Preoperative chemotherapy regimen were 5-FU and cisplatin d regimens of 2 to 4 cycles,such as FOLFOX-7 or XELOX or SOX,according to clinicians.The examination group received a continually Omega-3 Fish-oil supplement providing 2.0 g of eicosapentaenoic acid (EPA) and 1.0 g of docosahexaenoic acid (DHA) daily before operation.Finally,28 cases in each group entered the final analysis.Parenteral nutritional support were prescribed to patients with nutritional risk by NRS2002 assessment in both groups.There was no in-hospital death in either group.We compare the infection rate during the postoperative period and the length of hospital stay between the two groups.The Infections includes abdominal infection and non-abdominal infection.