<p>Medical disputes not only undermine the trust between doctors and patients and affect the effectiveness of treatment but also lead to social instability and increase the waste of medical resources. Compared to existing game theory-based conflict analysis method, graph model for conflict resolution (GMCR) provides a simple and effective analysis tool for real-world disputes. However, while traditional GMCR cannot perfectly resolve medical disputes under information asymmetry, the existing research on medical disputes ignores the impact of coalition among decision-makers (DMs) on stability analysis results under information asymmetry. Thus, to balance the contradiction between normal operation of hospitals and protection of personal interests among multiple DMs, this article proposes a coalition stability analysis method based on GMCR under information asymmetry, targeting the characteristics of unequal status and easily forming coalitions of participants in conflicts. First, each DM’s information preference matrix and information reachable matrix are constructed by determining whether each DM is influenced by information and from which leader DMs the influence of information comes. Second, by using an enumeration method to list all possible coalitions of sanctioning opponents, the information preference relationships of coalitions are constructed and logical and matrix expressions of coalition stability with the influence of information are defined on the basis of full coalition set and universal coalition set. Finally, a case study of real-life medical disputes is conducted to verify the feasibility and effectiveness of the proposed method, maintaining social stability, safeguarding patient rights, and maintaining normal hospital operations.</p>