Nitrogen hypoxia has recently emerged as a method of execution in the USA, with Alabama conducting the first executions using this technique in 2024. This article examines the historical evolution, medicalisation and ethical dilemmas surrounding execution practices, with particular attention to the rise of nitrogen hypoxia. Drawing on a targeted review of medical, legal and ethical literature, we explore the development of lethal injection protocols, the legal and procedural drivers of nitrogen gas adoption and the complex role of healthcare professionals in executions. Central concerns include the experimental nature of nitrogen hypoxia, the lack of transparency in execution protocols and the ethical implications of involving clinicians in state-sanctioned killing. We argue that the conflation of medical tools with punitive practices obscures fundamental distinctions between clinical care and capital punishment, raising urgent questions about professional integrity and public trust. Ultimately, we call for greater clarity, ethical consistency and transparency in addressing the interplay of medicine, law and the death penalty. By confronting these issues, we underscore the critical role of the medical community in advocating for humane practices and fostering informed public and legislative discourse on the intersection of medicine, ethics and capital punishment. We aim to contribute to the ongoing debate on the ethical and procedural challenges of state-sanctioned executions and the responsibilities of healthcare professionals.