eng International Academy of Ecology and Environmental Sciences Network Pharmacology 2415-1084 2026-6-1 11 1-2 1 61 1 article WenJun Zhang 1 2 School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China In present study, a multi-source GWAS (Genome-Wide Association Study) data fetchor for Mendelian Randomization (MR) analysis was presented. The data fetcher is a web-based application designed to automate the retrieval of genome-wide association study (GWAS) summary statistics from multiple public databases. It facilitates Mendelian Randomization (MR) analysis by allowing researchers to search multiple GWAS databases simultaneously, map phenotypes across different nomenclature systems, filter results by statistical significance thresholds, download results in standardized CSV format, and support both univariable and multivariable MR designs. In the fetchor, the inputs are exposure trait(s) (variable(s)) and outcome trait (variable), the outputs are GWAS exposure and outcome data. http://www.iaees.org/publications/journals/np/articles/2026-11(1-2)/a-multi-source-GWAS-data-fetcher.pdf GWAS data fetcher Mendelian Randomization (MR) web-based tool