TLR4 and fatty liver disease: This article systematically reviews the research progress on how flavonoids, triterpenoids, alkaloids, and polysaccharides improve hepatic steatosis, inflammatory responses, and metabolic disorders from a toxicological perspective by reshaping the intestinal microbiota, repairing the intestinal mucosal barrier, regulating short-chain fatty acid and bile acid metabolism, and synergistically acting on signaling pathways such as TLR4/NF-kB, FXR, TGR5, SIRT1, and the NLRP3 inflammasome.