Public health policies designed to improve individual and population health may involve coercion. These coercive policies require ethical justification, and yet it is unclear in the public health ethics literature which ethical concepts might justify coercion, and what their limitations are in applying across contexts. In this paper, we analyse a number of concepts from Western bioethics, including the harm principle, paternalism, the public interest, and a duty of easy rescue. We find them plausible justifications for coercion in theory, but when applied to case studies, including HIV testing in Malawi, vaccine mandates in South Africa, and prohibitions of antibiotic use in livestock in the EU, their limitations become clear. We argue that the context-specificity of ethical justifications for coercion has been overlooked, and there is more work needed to identify context-relevant ethical justifications for coercive policies in various settings and for various populations, rather than relying on universalising Western bioethical justifications across all contexts.