ObjectiveTo systematically review the association between angiotensin-converting enzyme inhibitors (ACEIs)/angiotensin receptor blockers (ARBs) therapy and digestive system neoplasms.MethodsPubMed, EMbase, The Cochrane Library, CNKI, WanFang Data, VIP and CBM databases were searched from inception to February 2017 to collect studies about ACEIs/ARBs therapy and risk of digestive system neoplasms or survival of digestive system neoplasms patients. Two reviewers independently screened the literature, extracted the data and evaluated the risk of bias of included studies, then meta-analysis was performed using Stata 12.0 software.ResultsA total of 21 articles including 32 studies were included. The results of meta-analysis showed that ACEIs/ARBs therapy could reduce the risk of colorectal cancer (OR=0.92, 95%CI 0.86 to 0.99, P=0.023), but there were no relationships between ACEIs/ARBs therapy and the risk of liver cancer or gastric cancer. ACEIs/ARBs therapy could improve the survival of colorectal cancer patients (HR=0.79, 95%CI 0.63 to 0.98, P=0.031), but there was no association between ACEIs/ARBs therapy and the survival of pancreatic cancer patients (HR=0.75, 95%CI 0.50 to 1.13, P=0.165).ConclusionACEIs/ARBs therapy may reduce the risk of colorectal cancer, as well as improve the survival of colorectal cancer patients, but there are no significant relationships between ACEIs/ARBs therapy and the risk or the survival of other digestive system neoplasms, such as liver cancer, gastric cancer and pancreatic cancer. Due to limited quality and quantity of the included studies, more high quality studies are needed to verify above conclusion.