The systemic consequences of periodontitis via the oral–gut axis have garnered increasing attention, yet two critical gaps persist: (1) the role of host-derived mediators in bridging oral inflammation to gut pathology remains underexplored, and (2) the dual effects of HGF, a regulator of periodontal destruction, on intestinal homeostasis are paradoxically unresolved. This evidence concerns the gene HGF and periodontitis.