Our univariable MR using inverse-variance weight method identified causal associations of IL-2ra (OR: 0.892, 95%CI: 0.828–0.961, p = 0.003), MIG (OR: 1.124, 95%CI: 1.046–1.207, p = 0.001) and IL-18 (OR: 0.912, 95%CI: 0.852–0.977, p = 0.008) with gastric polyp, MIP1b (OR: 0.956, 95%CI: 0.927–0.987, p = 0.005) and IL-6 (OR: 0.931, 95%CI: 0.870–0.995, p = 0.035) with colonic polyp and IL-9 (OR: 0.523, 95%CI: 0.345–0.794, p = 0.0007) with gallbladder polyp. This evidence concerns the gene IL18 and stomach polyp.