The urgency of addressing climate change has accelerated the need for healthcare to mitigate its associated environmental harms. Co-benefits approaches are being used in policymaking to frame mitigation actions because they promise to deliver better health outcomes alongside environment benefits. Despite this, little empirical data exists on public perceptions about the acceptability and usefulness of this approach. We conducted 12 focus groups with 82 members of the UK public asking the question: what were participants' values, beliefs and experiences about the environmental harms associated with healthcare and how should these issues be conceptualised and addressed? Co-benefits framings resonated with participants, who perceived this approach as useful for prioritising healthcare needs while valuing the environment. However, when participants tried to frame co-benefits as a solution, they struggled to reconcile complexities. Furthermore, their discussions revealed a certain subjectivity and context-specificity in co-benefits framing, drawn from their own experiences and expectations of care. We emphasise paying attention to such subjectivities when developing co-benefits policies. This could be achieved by the inclusion of public and patient voices in policymaking. Any underlying assumptions associated with co-benefits policies-including which subjectivities are used in the framing and how tensions are resolved-must be made transparent.