The main goal of chemomechanical preparation is to remove microorganisms, pulp tissue remnants and dentine debris from the root canal system. Irrigation plays a major role in the cleaning and disinfection of the root canal. A large number of chemical compounds have been suggested over the years for use as irrigants during root canal treatment. At the moment there is no single irrigant that can satisfy all of these requirements, so a combination of irrigants is frequently used during treatment while seeking a balance between efficacy and safety. However, the need to use more than one solution also brings additional challenges because they may interact with each other inside the root canal. The aim of this article is to provide a critical review of the current evidence on the properties of the root canal irrigants, focusing particularly on those that are most widely used. Keywords: endodontics, interactions, irrigating solutions, properties, root canal irrigation