Objective: To compare the different prognosis between enteral nutrition (EN) and parenteral nutrition (PN) in patients after gastrointestinal surgery (GIS), and to investigate a reasonable regimen of enteral nutrition (EN) after GIS. Methods: Randomized controlled trials (RCTs) on EN/PN after GIS from 1970 to 2008 retrieved from the data bank of Pubmed, EMBASE and Cochrane Library were analyzed. Evaluation endpoints were anastomotic dehiscence, infection (catheter sepsis, wound infection, pneumonia, intra-abdominal abscess and urinary tract infection), vomiting and abdominal distention, other complications, length of hospital stay and mortality rate. Results: Twenty-three RCTs including 2784 patients met the entering criteria. Compared with PN, EN was beneficial in the reduction of anastomotic dehiscence (RR = 0.67, 95%CI: 0.50 - 0.91; P = 0.010), infections (RR = 0.72, 95% CI: 0.64 - 0.81; P < 0.001), other complication (RR = 0.82, 95%CI: 0.73 - 0.92; P < 0.001) and duration of hospital stay (weighted mean difference: -3.60; 95%CI: -3.88 - -3.32; P < 0.001). But the risk of vomiting was increased among patients with EN (RR = 1.39, 95%CI: 1.21 - 1.59; P < 0.001), and there was no significant differences in mortalities between the two groups (P = 0.400)Conclusions: There is no advantage in treating patients 'nil by mouth' after gastrointestinal surgery. It indicated that early commencement of enteral feeding is beneficial.