Our study investigated the causal relationship of seven common antidiabetic drug targets–metformin, GLP-1 receptor agonists, SGLT2 inhibitors, DPP-4 inhibitors, insulin and its analogs, thiazolidinediones, sulfonylureas and alpha-glucosidase inhibitors–on various gastrointestinal diseases. The gene discussed is GLP1R; the disease is gastrointestinal disease.