The Declaration of Helsinki, as a fundamental document of ethics in medical research involving human participants, has been periodically revised since its adoption in accordance with theoretical and scientific advancements, emerging ethical issues in research, and the experiences gained over time. In the latest revision completed in 2024, significant changes and amendments have been made. This study examined the changes and revisions made in the latest version of the declaration in comparison to its previous version from 2013. Fundamental revisions in the recent update include a requirement for adherence to ethical principles in research not only by physicians but also by other researchers, the replacement of “subject” with “participant,” and the emphasis on the voluntary nature of informed consent. Attention to environmental sustainability, precise design to prevent research waste, and a focus on scientific integrity are among the other amendments in the new revision of this declaration. Other modifications and revisions made in the recent edition include the promotion of individual and public health as the ultimate purpose of research, the provision of sufficient resources for research ethics committees and strengthening their independence, the importance of local ethical review, consideration of the preferences and values of participants who are unable to provide voluntary and informed consent, and the necessity of adhering to the ethical principles of the declaration during public health crises and emergencies. Given the changes made, it is recommended that the national ethical guidelines for medical research involving human participants in Iran be revised based on the 2024 revisions.
