Quorum sensing (QS) is a communication mechanism among bacteria which allow to control specific processes such as bio-film formation, expression of virulence factors, secondary metabolite production, and stress resistance mechanisms. Language used for intra-cell communication is based on small signal producing molecules named auto-inductors (Acyl homosiderina lactone), which may regulate bacterial environment according to population density. There are many species of microorganisms, plants and algae, capable of inhibiting the QS in pathogenic and symbiotic bacteria, by producing secondary metabolites. Therefore, the QS is an important target in search of and design new active principles useful in therapeutic.