Finally, our MR-BMA analysis prioritized MIG (MIP = 0.332, MACE = 0.022; PP: 0.264, MSCE = 0.059), IL-18 (MIP = 0.302, MACE = −0.020; PP: 0.243, MSCE = −0.059) and IL-2ra (MIP: 0.129; MACE: −0.005; PP: 0.112, MSCE: −0.031) for gastric polyp, and MIP1b (MIP = 0.752, MACE = −0.033; PP: 0.665, MSCE = −0.044) and IL-6 (MIP: 0.196; MACE: −0.012; PP: 0.140, MSCE: −0.064) for colonic polyp, and IL-9 (MIP = 0.936, MACE = −0.446; PP: 0.781, MSCE = −0.478) for gallbladder polyp as the top-ranked protective factors. The gene discussed is IL9; the disease is polyp of gallbladder.