In these treatments, gut microbiota mainly affects hyperlipidaemia through the following mechanisms: (1) Intervention in bile acid synthesis, such as gut microbiota intervening in bile acid synthesis by controlling the metabolism of recombinant cytochrome P450 7A1 (CYP7A1) and trimethylamine n-oxide (TAMO), and regulating cholesterol metabolism through the fibroblast growth factor 15 (FGF15)-ATP-binding cassette sub-family G member 5/8 (ABCG5/G8) pathway by affecting farnesoid X receptor (FXR). The gene discussed is CYP7A1; the disease is hyperlipidemia.