Successful root canal therapy depends on thorough debridement of pulpal tissue, dentin debris and infective microorganisms. Currently, it is impossible to predictably eradicate intraradicular infection with mechanical instrumentation alone. Therefore, irrigants are required to be used as an important addition in the disinfection process. Elimination of organic tissue and reduction of the microbial bio-burden remain a difficult task, especially in the apical-third of the root canal system because of anatomical irregularities. Microorganisms residing in these complex areas may flourish if they are not properly removed during the chemo-mechanical preparation of the canal. Therefore, it has been established that to successfully clean this apical area, irrigants should be used. Optimal and effective irrigation is achieved by the use of two or combination of several irrigants, used in a specific sequence. This book gives an insight about various irrigating solutions, their properties and their mechanism of action, interactions among them and gives a perspective into the future of root canal disinfection.