With the rapidly development of computing science and information technology and their wide use in health and medical area, huge amounts of data sets have been produced during medical service, health care and health management, which consists of the health and medical big data. Many countries around the world have recognized that big data have profound effects on improving the medical service and promoting the health industry. Some of the developed countries have launched national big data initiatives and put them in practice. This paper briefly introduced the background and progress of big data, with an emphasis on the main content, application areas, challenges and trends of the health and medical big data development.