Antimicrobial resistance (AMR) has been clearly identified as a major global health challenge. It is a leading cause of human deaths and also has a toll on animals, plants, and the environment. Despite the considerable socio-economic impacts, the level of awareness of the problem remains woefully inadequate, and antimicrobials are not generally recognized as a global common good, one that everyone has a role and responsibility to conserve. It is imperative for antimicrobial stewardship to be more widely implemented to achieve better control of the AMR phenomenon. The Food and Agriculture Organization (FAO) of the United Nations plays an important role in promoting and facilitating antimicrobial stewardship. The specific needs to be addressed and barriers to be overcome, in particular, in low- and middle-income countries in order to implement antimicrobial stewardship practices in agrifood systems are being identified. As a global community, it is essential that we now move beyond discussing the AMR problem and focus on implementing solutions. Thus, FAO provides multi-pronged support for nations to improve antimicrobial stewardship through programs to strengthen governance, increase awareness, develop and enhance AMR surveillance, and implement best practices related to antimicrobial resistance in agrifood systems. For example, FAO is developing a platform to collect data on AMR in animals and antimicrobial use (AMU) in plants (InFARM), working on a campaign to reduce the need to use antimicrobials, studying the use of alternatives to the use of antimicrobials (especially those used for growth promotion) and actively promoting the implementation of the Codex Alimentarius AMR standards. Together, these will contribute to the control of AMR and also bring us closer to the achievement of multiple sustainable development goals.

The One Health approach is increasingly recognised as a holistic solution to complex global health and ecological challenges. Legislation is of utmost relevance for its effective implementation, providing a mechanism to institutionalise intersectoral and interdisciplinary collaboration, clarify responsibilities and promote sustainability. However, the legal nature of One Health remains underexplored. This paper examines how the key underlying principles of One Health align with legal principles and concepts broadly recognised by legal literature and jurisprudence, including those articulated in the Rio Declaration and the International Law Association’s New Delhi Declaration on principles of international law relating to sustainable development. Emphasis is placed on the principle of integration, a cornerstone of sustainable development that offers a pathway to operationalise One Health within legal frameworks. By conceptualising One Health as an extension and practical application of the principle of integration, this paper advances its legal characterisation, embedding it within broader principles of international law. One Health is positioned as a legal construct, providing a pathway for its implementation through law and affirming its role as an integral component of sustainable development.

One Health is an approach to managing complex health threats by promoting multisectoral and multidisciplinary collaboration, engaging stakeholders, and contributing to sustainable development, while fostering equity and socioecological equilibrium across sectors and living species. Legislation is crucial for advancing One Health by establishing structures that foster collaboration, define roles and responsibilities, and support sustainable outcomes. To enhance its effectiveness, One Health must be integrated into legal frameworks addressing global challenges at the intersection of human, animal, plant, and ecosystem health, through flexible, context-specific legal frameworks adaptable to emerging and evolving threats. This paper identifies four legal elements for embedding One Health into legislation: (i) normative integration (bridging different legal domains); (ii) multisectoral and multidisciplinary collaboration; (iii) stewardship and the sustainable management of common goods beyond human interests; and (iv) stakeholder engagement, ensuring inclusive participation. These elements are interconnected and interdependent, collectively forming a comprehensive foundation for integrating One Health into legal frameworks. They have the potential to dismantle sectoral silos, foster multidisciplinary collaboration, and advance stakeholder engagement and the recognition of the intrinsic value of all species. At the same time, these elements also function as strategies, offering practical pathways for legislative design and implementation. The paper also provides examples of their implementation and suggests avenues for future research.

Resumen: Una sola salud es un enfoque integrado que reconoce la interdependencia entre la salud humana, animal, vegetal y ambiental. Aunque inicialmente se centró en la prevención de zoonosis, su evolución ha consolidado su función como estrategia preventiva e integradora frente a desafíos sanitarios y ecológicos complejos que requieren respuestas multisectoriales, como las pandemias, la resistencia a los antimicrobianos, el cambio climático y la contaminación. La aplicación del enfoque Una sola salud exige marcos de gobernanza flexibles, que integren competencias y responsabilidades diversas, superen barreras normativas y refuercen la colaboración y coordinación entre sectores tradicionalmente desconectados. El derecho puede desempeñar un papel clave en su implementación, a través de marcos jurídicos suficientemente flexibles como para adaptarse a los avances científicos, facilitar la cooperación interinstitucional e interdisciplinaria, y garantizar la participación y la consideración de la salud y el bienestar de las diferentes especies en la toma de decisiones. Este artículo propone una lectura jurídica de Una sola salud, examinando su origen y evolución conceptual. Analiza su gobernanza, identifica ejemplos de aplicación a nivel nacional y regional, y propone su consideración como un principio orientador y flexible. Finalmente, se analiza cómo la Unión Europea ha integrado progresivamente este enfoque en sus políticas e instrumentos jurídicos, incluida su incorporación al Pacto Verde Europeo y su aplicación a sectores como la biodiversidad, el cambio climático y la salud pública. One Health is an integrated approach that recognizes the interdependence between human, animal, plant, and environmental health. Initially focused on the prevention of zoonoses, its evolution has strengthened its role as a preventive and integrative strategy to address complex health and ecological challenges that require multisectoral responses, such as pandemics, antimicrobial resistance, climate change, and pollution. The implementation of One Health requires adaptive governance structures that integrate diverse competencies and responsibilities, overcome normative barriers, and strengthen collaboration and coordination among traditionally isolated sectors. Law plays a crucial role by providing flexible legal frameworks, adaptable to scientific advances, facilitating cooperation between different institutional areas and disciplines, ensuring participation, and taking into account the health and well-being of various species in decision-making. This article proposes a legal reading of One Health, analyzing its origin and conceptual evolution. It examines the governance of this approach, identifies national responses to its implementation, and promotes the role of law by proposing its categorization as a guiding and flexible principle. Finally, it explores how the European Union has progressively integrated this approach into its policies and legal instruments, including its incorporation into the European Green Deal and its operationalization in sectors such as biodiversity, climate change, and public health. Palabras clave: Una sola salud. Enfoques integrados. Gobernanza integrada. Bienes universales. Equidad entre especies. Salud global. Derecho sanitario. Pandemias. Derecho ambiental. Principio de precaución. Principio jurídico. Política sanitaria. Integración. Unión Europea. Key Words: One Health. Integrated approaches. Integrated governance. Universal goods. Equity among species. Global health. Global health law. Pandemics. Environmental law. Precautionary principle. Legal principle. Health policy. Integration. European Union. Índice: 1. Introducción 2. Qué es “Una sola salud”: definición e historia de un concepto en evolución 3. La compleja cuestión de la gobernanza de Una sola salud 4. El derecho como vía para la implementación del enfoque Una sola salud 5. Una sola salud como principio jurídico 6. Una sola salud en la Unión Europea 7. Conclusiones 8. Anexo bibliográfico, normativo y documental Table of Contents: 1. Introduction 2. What is “One Health”: Definition and History of an Evolving Concept 3. The Complex Issue of One Health Governance 4. Law as a Pathway for Implementing the One Health Approach 5. One Health as a Legal Principle 6. One Health in the European Union 7. Conclusions 8. Bibliography

This research question seeks to explore the role of governance and legislation in fostering an enabling environment for the effective implementation of a One Health approach to complex challenges at the human–animal–environment interface. It calls for the identification of legal entry points for integrating One Health into international, regional and national legal frameworks and governance mechanisms governing global sustainability and complex health challenges (including pandemic preparedness and response, food system transformation and climate change, biodiversity loss, environmental protection and pollution control). Additionally, it invites to analyse the alignment of international, regional and national legal instruments with the demand for One Health implementation.

La contaminació és una greu crisi global que contribueix a la pèrdua de biodiversitat, el canvi climàtic i suposa greus riscos per a la salut de tots els éssers vius, especialment dels més vulnerables. L’ús generalitzat de substàncies químiques perilloses agreuja aquesta problemàtica, contaminant els ecosistemes i alterant el seu equilibri ecològic. Tot i que existeixen marcs normatius per a la seva regulació, aquests solen estar fragmentats i manquen d’un enfocament integral que aborde eficaçment els impactes intersectorials de la contaminació. Aquest article defensa la incorporació de l’enfocament d’Una sola salut (One Health) a la regulació de la contaminació, reconeixent les interconnexions entre la salut pública, animal, vegetal i dels ecosistemes, així com els desafiaments comuns que la contaminació planteja per a totes les formes de vida. Amb un èmfasi en la contaminació derivada de l’agricultura, l’estudi analitza els marcs jurídics aplicables als agroquímics i explora oportunitats per a enfortir la legislació des d’una perspectiva d’Una Sola Salut (One Health). En fer-ho, es promou la transició cap a sistemes agroalimentaris sostenibles i es contribueix a l’assoliment d’objectius més amplis en matèria de salut pública i protecció ambiental