This study aims to explain the theoretical principles of laser-activated irrigation of root canals and give a concise critical review of previous studies about using lasers as a supplement to the chemo-mechanical treatment of root canals. The goal of endodontic treatment is to remove microorganisms, pulp tissue, and dentine debris from the root canals, in a procedure that involves mechanical instrumentation and chemical treatment with irrigants. However, endodontic treatment has certain limitations due to anatomical complexity and the presence of lateral canals. The conventional needle and syringe irrigation technique is insufficiently effective in disinfecting lateral canals and poses a risk for irrigation extrusion into the periapical area. To avoid these disadvantages of conventional rinsing, irrigation activation techniques are being developed to increase the dispersion of irrigants into the root canal system. With the advancement of laser technology, laser beams also found application in the technique of laser-activated irrigation (LAI) of root canals. By applying pulsed technology of erbium laser, the laser beam in the irrigant causes a photothermal effect and the creation of transient cavitations, which result in the formation of pressure shock waves and shear stress on the dentinal walls, which facilitates the removal of smear layer and bacterial biofilm. With further technological progress in laser technology, new techniques are being developed, including photon-induced photoacoustic streaming (PIPS) and shock wave enhanced emission of photoacoustic streaming (SWEEPS). Currently, there are not enough high-quality studies in the literature to recommend laser as a supplement to chemo-mechanical treatment.