 The human gut microbiota interacts extensively with the host through metabolic exchange and co-metabolism of substrates; thereby contribute to a variety of metabolic and immunologic mechanism in the human body. CAD is a major field of interest in microbiota research, and there have been several findings that connect the gut microbiota to CAD pathophysiology. First, microbiota was associated with metabolic syndrome, namely obesity and insulin resistance. It is hypothesized that gut microbiota may increase short-chain fatty acid, that eventually increase appetite, thus causing obesity. Another hypothesis is that gut microbiota endotoxins may translocate into the bloodstream, elicit inflammatory cascade that eventually promote atherosclerosis. Second, microbiota may also have a role in the development of atherosclerosis. In patients with symptomatic atherosclerosis, there is a unique microbiome pattern that may have pro-inflammatory characteristics. Recently, a unique microbial pattern was found among patients with high cardiovascular risk profile. Third, gut microbiota metabolize dietary phosphatidylcholine lecitine to produce the metabolite trimethylamine-N-oxide TMAO, which is associated with increased risk of cardiovascular events. 