PURPOSE: This paper aims to examine the ethical implications of capital punishment, with a focus on the recent use of nitrogen asphyxi-ation in the case of inmate Kenneth Eugene Smith. It seeks to reopen the discussion on the death penalty from a bio-ethical perspective, considering the sensory experience of death and its impact on both inmates and observers. METHODS: To analyze the case of Kenneth Eugene Smith, an in-depth search was conducted on scientific databases and international newspapers. Sources were selected to support the analysis of the case, including discussions on previous death penalty debates. Additionally, an overview of nitrogen usage and its physiological effects was provided. RESULTS: he execution of Kenneth Eugene Smith by nitrogen asphyxiation is described, highlighting observations made by witnesses and the prisoner's resistance. Discussion points include the prisoner's suffering, the execution method's lack of scientific study, and transparency. CONCLUSIONS: The paper, according to shared ethical principles, criticizes the execution method failure and calls for further research to analyze the psychic and physical distress experienced by the inmates. It advocates for a reevaluation of execution protocols to uphold human dignity and minimize suffering.