Healthcare big data represents a significant category of medical big data, and its applications facilitate precision services, clinical decision-making, and data-driven research. It also supports policy and public health initiatives to advance the big data heathcare industry. This chapter focuses on real-world data studies, highlighting their advantages as real-world evidence and addressing the associated ethical issues. We introduce the critical importance of real-world data for the development of hospital preparations and Traditional Chinese Medicine (TCM). Another emphasis is placed on the current state and emerging trends in TCM big data, key TCM big databases, and their applications in data-driven clinical decision-making and research.