This book covers a wide range of systemic conditions such as cardiovascular diseases, endocrine disorder, renal diseases, liver diseases, pulmonary diseases, immunosuppression and chemotherapy radiation therapy, prosthetic joint replacement, pregnancy, hemorrhagic disorders, blood dyscrasias and infectious diseases that either compromise periodontal treatment or require special precautions before therapy. The presence of systemic diseases in patients, requiring periodontal therapy, creates challenges for the management of such cases. Many patients seeking dental care have significant medical conditions that may alter both the course of their oral disease and the therapy provided. Therefore, the therapeutic responsibility of the clinician includes identification of the patient's medical problems to formulate proper treatment plans. The goal of holistic patient management is facilitated by a free flow of information between the patients and their medical and dental health care providers. For this reason, the clinician needs to be familiar with a large number of diseases and systemic/medical conditions and their consequences on periodontal management.