For some decades the doctor-patient relationship has been the central concern of medical ethics. This focus has marginalized public health issues by concentrating on individual patients and individual practitioners, and thereby on one aspect of medical structures in the richer parts of the world. It has often neglected questions about justice and health, and especially about international justice and health, and the medical problems of poorer parts of the world. A normatively adequate public health ethics needs to be anchored in political philosophy rather than in ethics. Its central ethical concerns are likely to include trust and justice, rather than autonomy and informed consent. To approach these concerns effectively it will be important to think realistically about obligations (and perhaps less about rights) as well as about the range of state and nonstate actors whose capabilities might enable them to discharge some of the obligations most relevant to health outcomes.