Abstract: Intestinal flora and its metabolites are inextricably associated with the development of heart failure (HF)."Gut hypothesis in HF" indicates that patients with cardiovascular diseases encounter gut flora imbalance and bacterial translocation, which can trigger systemic inflammatory response and eventually promote the progression of heart failure. Studies showed that a higher concentration of trimethylamine N-oxide (TMAO), a kind of intestinal metabolites, could induce the occurrence of cardiovascular adverse events through a variety of mechanisms (such as intensifying myocardial fibrosis, ventricular remodeling and progress of coronary plaque, aggravating water-sodium retention and systemic inflammatory response), and which is closely related to the survival and prognosis of patients with HF. These patients could benefit from the reducing TMAO. This article reviews the research advances of the relationship between intestinal flora or TMAO and heart failure.

Key words: heart failure, intestinal flora, trimethylamine N-oxide