Changes in the intestinal flora can affect the expression of liver drug enzymes and P-gp to a certain extent, and subsequently affect the transport and metabolism of oral anticoagulants (e.g., warfarin, dabigatracin, and rivaroxaban), leading to differences in the treatment efficacy of oral anticoagulants, and even cerebral hemorrhage, cerebral infarction and other serious adverse event. This evidence concerns the gene PGP and brain infarction.