The main objective of endodontic treatment is to eliminate microorganisms and prevent re-infection within the root canal. However, root canal infections are polymicrobial and difficult to eliminate due to anatomical complexity. Besides the instrumentation, irrigation is an important step for disinfection. However, because the traditional irrigants can be ineffective in some cases, there is increasing interest in alternative irrigation solutions such as chlorhexidine (CHX). CHX is a widely used medical antiseptic and disinfectant. It is a broad-spectrum antimicrobial agent and has a comparable antimicrobial efficiency as both a root canal irrigant and intracanal medicament. It also has unique properties such as residual antimicrobial effects. This paper presents the chemical, pharmacological and antimicrobial properties of CHX. In addition, an overview of the clinical applications and the pros and cons of the use of chlorhexidine in endodontics is presented. Schlagwörter: antimicrobial, chlorhexidine, disinfection, irrigation, substantivity