Abstract: Public health focuses on collective actions to address the health needs of populations. Public health ethics helps to guide the practice of public health with ethical principles and norms. As healthcare providers, medical workers and healthcare facilities are integral parts of the public health system. Daily clinical practice involves principles of not only clinical medical ethics but also public health ethics. In the context of combating the outbreak of an infectious disease, public health ethics plays a significant role in clinical practice. We briefly overview the definition and principles of public health ethics, and introduce three substantive ethical questions that are central to public health and may be encountered in clinical practice.