The emerging role of the intestinal microbiota and of microbial metabolites in both host health and different pathological conditions, including the metabolic syndrome, has opened new avenues for the development of novel diagnosis and therapeutic tools targeting gut microbiota. However, the complex causal mechanisms, interactions between microbiota, host and environmental factors (particularly diet), as well as the involved bioactive metabolites have not been unveiled yet. Most of the performed studies have demonstrated this causality in animal models, and less in humans. The purpose of this chapter is to present a brief overview regarding the role of microbial metabolites in the development of host metabolic syndrome.