AbstractBacterial density-dependent intercellular communication systems known as Quorum Sensing (QS) play a key role in regulating numerous physiological processes that determine the interactions of microorganisms with their hosts and environment. Ways of suppressing QS, or Quorum Quenching (QQ), are considered a promising approach for controlling pathogenicity and other undesirable bacterial traits, stimulating an active search for new QS inhibitors. One of the best-studied QQ mechanisms to date is the enzymatic hydrolysis of autoinducers-N-acyl-homoserine lactones (AHLs). This review systematizes data on the potential sources of QQ enzymes and discusses their main classes and specificity of action. The ecological significance of QQ mechanisms is discussed. Various approaches to the use of QQ enzymes in medicine, industry, and agriculture are analyzed.