Health care is a tremendously expensive service that deeply impacts the daily life of individuals. It has become crucial to understand all the factors that influence the usage of these services. Word-of-mouth (WOM) is such a factor, because it strongly affects the health behavior. A research gap exists when it comes to the analysis of the current state of WOM research in the health care sector. Based on a comprehensive literature review of the leading scientific journals in the health care sector, this paper investigates existing WOM studies. The investigated studies emphasize hospital recommendations as well as the necessary preconditions for WOM. The studies highlight that there are factors which are favorable to WOM and might be influenced by service providers and payers. Fewer studies concerned the spread and impact dimension. In this regard it is somewhat unexpected that three times more studies focus on the preconditions for WOM than the actual impact of WOM. Only a small number of electronic WOM studies could be found. Stakeholder theory suggests emphasizing factors which benefit WOM. As WOM might spread in networks and influence large groups of people, stakeholder theory further proposes considering WOM as a possible way to distribute specific health care recommendations. Even if the studies highlight the importance of WOM, several research gaps still exist. For example, due to the strong focus on hospitals, recent research seems to neglect WOM concerning health care providers such as a general practitioners or nursing homes.