The article analyzes the literature on the clinical significance of passive ultrasonic irrigation (PUI). as a method of increasing the effectiveness of disinfection of the root canal system. The relevance of using PUI in the treatment of complex anatomical forms of root canals is substantiated. The physicohydrodynamic mechanism of action of PUI, which is based on acoustic streaming and cavitation, is discussed. This mechanism enhances the antimicrobial effect of irrigation solutions. Special attention is paid to the specifics of the use of various solutions — sodium hypochlorite, ethylenediaminetetraacetic acid and chlorhexidine. The advantage of PUI in removing biofilms and solid residues compared to non-activated irrigation is reflected. Data on reduced viability of Enterococcus faecalis, reduction of postoperative pain, and reduced need for analgesics when using PUI are presented. The influence of PUI on the bond strength of restoration materials with the dentin of the pulp chamber is considered. Data indicating potential complications such as perforations and maladaptation of the filling material are presented.