Background: The objective of this study was to assess whether the use of staple line reinforcement (SLR) reduces staple line complications (SLC). Mechanical staple lines are essential for gastrointestinal surgery such as bariatric surgery. However, SLC, such as bleeding and leakage, still occur. The purposes of this study were to provide quantitative evidence on the relative efficacy of gastric SLR and to compare the rates of effectiveness of three commonly used methods., Methods: A search of the medical literature in English language journals identified studies from Jan 1, 2000, to Dec 31, 2013, using the following reinforcement types: (1) no reinforcement, (2) oversewing, (3) a biocompatible glycolide copolymer, and (4) bovine pericardium after gastric bypasses and sleeve gastrectomies. Types of reinforcement were compared using a random-effects model., Results: This meta-analysis reviewed 16,967 articles, extracting data on 56,309 patients concerning leak and 41,864 patients concerning bleeding. Over 40 % of patients had no reinforcement, resulting in the highest leak rate (2.75 %) and bleed rate (3.45 %). Overall, reinforcing with bovine pericardium had the lowest leak (1.28 %) and bleed (1.23 %) rates. Suture oversewing was better than no reinforcement but not as effective as bovine pericardium for leak (2.45 %) and bleed (2.69 %) rates. Buttressing with a biocompatible glycolide copolymer resulted in the second highest leak rate (2.61 %) and a bleed rate of 2.48 % but had significantly lower bleed rates than no reinforcement., Conclusions: SLR provided superior results for patients compared to no reinforcement for reducing SLC. Buttressing with bovine pericardium resulted in the most favorable outcomes. The effectiveness of different methods used to reinforce the staple line in gastric surgery does not appear to be equal.