The present study concludes that BioPure MTAD is as effective against E. faecalis as 5.25% NaOCl and more effective than 2% CHX. CLINICAL SIGNIFCANCE: E. faecalis is one of the most resistant intracanal species and a possible cause of root canal failure. Many authors have stressed the importance of using antimicrobial irrigants during chemomechanical preparation to ensure complete disinfection. Therefore, various irrigating solutions have been used during and immediately after root canal preparation to remove debris and necrotic pulp tissue and to eliminate microorganisms that cannot be reached by mechanical instrumentation.