Abstract
Japanese Medical Association has an arbitration system to solve medical malpractice controversies although its entire procedures are in camera. To look at various sources on medical controversies in Japan, we estimate that only ten percent of medical controversies go to courts and only one percent of all controversies result in verdicts for patients. Medical maloccurrences are not outcomes of mere carelessness. We need to check the incidental factors which induced individual carelessness. To prevent real accidents, we should investigate near miss incidents. Heinlich's law on workers' accidents shows that one accident with serious injuries exists with twenty-nine accidents with minor injuries and three hundred incidents without any injury. Furthermore, it is very important to keep fine relationship and good communication not only among healthcare providers but also between providers and patients in order to avoid the increase of medical malpractice controversies.