The links between oral and general health have been increasingly recognized over the past two decades. It is well known that partial symptoms of the systemic disease often appear in the mouth, on the other hand, some systemic diseases are caused by oral diseases. Furthermore, there is mounting evidence that oral condition contributes to infectious complications following surgery, such as postoperative pneumonia or surgical site infection. Now, I am the director of the Perioperative oral care support center, and I examine the oral condition of all patients whose stay in the hospital are due to systemic diseases. Hence, I would like to show some cases that indicate interactive relationship between systemic diseases and oral diseases, and discuss with everyone about the importance of the dento-maxillo- facial radiographic examinations for the patients with systemic diseases.