The Office of the Chief Medical Examiner practices Forensic Pathology for the City and County of San Francisco. The legal purpose of the Chief Medical Examiner is to protect the public health and legal requirements of the County relating to Forensic Pathology. The Medical Examiner is appointed by law to many responsibilities, the foremost of which is the investigation and certification of a variety of deaths of legal or public health interest. The Chief Medical Examiner is required, by law, to determine the cause, circumstances and manner of death for those cases found to be under the Office's legal jurisdiction. Those deaths that are due to the sequelae of natural disease are not reportable to the Medical Examiner, and the responsible treating physician can properly complete the Death Certificate. However, all deaths in which there is some reason to believe that the death is not due to a natural disease process, is a homicide, suicide, accident or one of the many types of deaths mentioned by law, must be reported to the office. Only Medical Examiners can investigate and sign the Death Certificate if the death is related to a homicide, suicide, accident, a patient with no attending physician, an industrial related death, an unidentified person or where there is some medical reason to consider that the death might be due to a contagious disease. In addition to the work that is performed in accordance with the various sections of local, State and Federal Laws, examination of living persons is performed for a number of purposes. Adults and children are examined to evaluate injuries or to collect evidence. The Forensic Laboratory of the Office of the Chief Medical Examiner performs drug and poison analysis for the County. This work includes analysis of blood and urine in cases of driving under the influence of alcohol or drugs. The results of any examination or testing are often presented as expert testimony in the criminal courts of the County.