Informative data for public health reform against impacts of unsustainable environmental degradation is fragmented across disciplines, while discreet and spatial evidence is particularly limited for marine and coastal ecosystems. For poor, marginal communities experiencing limitations in health sector interventions, such knowledge could be vital. We investigated mangrove-health relationships in Ghana to inform identification and design of most suitable health-supporting ecosystem interventions in such societies. Academic, health, media, and conservation key informants were interviewed alongside mangrove residents, about influences of human-mangrove interactions on health, and consequences of ecosystem and health sector interventions. Reports show that mangroves diversely supply vital health-impacting ecosystem services, support services for fisheries being the strongest health link. Efficacies and constituents of mangrove-sourced medicines remain unverified, and while reliance on these has declined over time, some minimal indigenous knowledge yet survives. Little knowledge about pollution remediation services of mangroves emerged, with disease vector and pathogen regulation perceived as health disservices. These findings elucidate and reaffirm aspects of the neglected but crucial mangrove-health nexus, for which further exploration constitutes a compelling nature-based opportunity to enhance wellbeing in marginal societies. Mangrove ecosystem interventions maximise economic benefits that expand access to wider health improvement options, but social and rural-urban public health success disparities persist. Customization of conservation strategies can elicit preferred health impacts, offset shortfalls in non-uniform implementation of health sector interventions and guarantee more equitable and sustainable cross-sector outcomes.