One Health faces enormous pressure and challenges as it attempts to mitigate dynamic, surprising and complex global events that threaten the health and sustainability of human and animal populations and the biosphere. One Health practitioners and researchers need every advantage to developing working solutions to the world's imminent complex issues. Heath promotion and harm reduction, interrelated approaches that have seen much success over decades of use in global public health, may be important models to consider. Both use an upstream socioecological determinant of health approach to reach beyond the health sector in all health efforts, and encourage active community participation and empowerment to attain and sustain human and ecological health. This scoping review of 411 documents, believed to be the first to relate health promotion and harm reduction to One Health, searched self-declared One Health research literature for evidence of health promotion and harm reduction policies, principles and methodologies. It sought to answer the questions: "What is the scope of practice of One Health in self-declared One Health publications?" and "Are attributes of health promotion and harm reduction found in self-declared One Health-reviewed research literature?" Over half of the papers revealed no health promotion or harm reduction attributes while 7% were well-endowed with these attributes. These 7% of papers focused on deep-seated, complex health issues with systemic knowledge gaps and decision-making issues revolving around specific population vulnerabilities, social inequities and competing stakeholders. Implementing 'on the ground change' was a common theme in the strongest health promotion/harm reduction papers we identified. Alternatively, papers lacking health promotion or harm reduction attributes focused on managing proximate risks, primarily for infectious diseases. The addition of health promotion and harm reduction to One Health practices may help the field rise to the growing expectations for its involvement in complex global issues like pandemics and climate change.
