Health care research focuses on the description and analysis of the health care system and its requirements. Research-derived innovations are the subject of trials and evaluation of the transfer to daily routine. For this purpose health care research has developed a broad theory-based spectrum of methods. On the other hand, the concept of big data is an new informatics-driven approach to large data sets independent of content. With its technical vocabulary the concept of big data does not easily fit into traditional health care research. Central tasks of health care research such as the generation of theories, norm-oriented evaluations or proof of causality can neither be supported nor replaced by big data. However, the concept of big data has the potential to support health care research, with traditional tasks such as data linkage, analysis of health care paths, quick access to up-to-date data on the distribution and acceptance of health care services, as well as prediction and the generation of hypotheses. The prerequisite for all this is a trust-based linkage of different medical and nonmedical data sources on the basis of the legal regulation of data access and data protection.