Bacterial Biofilm has been shown to be the primary etiological factor in the initiation of periodontal diseases. The precise nature of the host inflammatory response is still an area of intense research. host modulation therapy refers to a treatment concept in which drugs are used as an adjunct to conventional therapies. Therefore, the successful long-term management of this disease may require a treatment strategy by integrating therapies that will address both causative components. In addition to these extensively studied groups of drugs, newer therapeutic approaches have also been tried. Most of these approaches are still in the infancy and limited to animal experimental studies only. This book highlights the important aspects of host modulation in periodontics.