This paper situates Korean tobacco litigation within the historical context of integrating medical expert testimony into the judicial process, in order to critically examine the implications of the medicalization of the judicial system. The paper analyzes the tobacco lawsuit filed in 1999 as public interest litigation in Korea, focusing on the medical expert report introduced in 2004 to evaluate the causal link between smoking and lung cancer, as well as the surrounding expert controversies. It explores how these expert deliberations, while making public knowledge of tobacco’s harms visible, simultaneously increased the demand for evidentiary clarity within the discursive framework of legal liability. The panel of medical experts was required to substantiate its conclusions in a detailed supplemental report, while the court, in turn, faced structural pressure to translate these expert findings into a final legal judgment. By discussing the role of medical evidence in the courtroom as revealed in the Korean tobacco litigation, this paper provides a historical reflection on the interaction and consensus-building process between medicine and law. It aims to offer a reflective foundation for integrating the values of public health and social responsibility into the legal discourse of liability.