The success of endodontic treatment derives from the complete elimination of microorganisms capable of causing an intraradicular or extraradicular infection. To achieve a more effective eradication of these microorganisms, endodontic instrumentation must always be implemented with abundant irrigation, which has to achieve chemical, mechanical and biological effects. The irrigators most used today are NaOCl, CHX and EDTA, released into the ducts through different techniques such as syringe, manual agitation, positive or negative apical pressure, sonic or ultrasonic activation, PIPS and PDT. The objective of this review is to update the different irrigating solutions and intracanal disinfection drugs, as well as to establish an irrigation protocol in the endodontic treatment. Material and Methods: Systematic search of scientific articles in the databases Pub Med, Medline and Google Scholar, with the following keywords Endodontic, Infection, Failure, Irrigation, Retreatment and Irrigation protocol. The exclusion criteria were “case report” articles and articles with a publication date prior to 2000. Results: 48 articles that met the inclusion criteria were analyzed. Comparing the different articles it can be seen that the NaOCl is the “gold standard” in terms of immediate antimicrobial efficacy, followed by the CHX that has a long-term antibacterial effect. As an intra-conductive drug it is advisable to use the combination of Ca (OH) 2 with CPMC. Conclusions: The most adequate irrigation protocol consists of using 2.5% NaOCl activated with ultrasound followed by a final wash with 7% MA or 0.2% CTR combined with 2% CHX. Key words: Endodontic failure, endodontic infection, Enterococcus faecalis, endodontic retreatment, irrigation, sodium hypochlorite, irrigation protocol.