This document assists policy-makers, health care providers and researchers to understand key concepts in health ethics and to identify basic ethical questions surrounding health and health care. It illustrates the challenges of applying ethical principles to global public health and outlines practical strategies for dealing with those challenges. The document is divided into four main parts. The first part explores key concepts in health ethics and explains common terms, theories and principles. The second part examines the main challenges in the practice of health ethics from the perspective of global public health. These issues provide the reader with a concrete understanding of the various ethical obstacles that may arise in public health, health research, and the provision of health care services. The third part describes practical strategies for dealing with these challenges and the key actors involved in developing ethical frameworks. Finally, the fourth part explains why health ethics is important to WHO, and how WHO supports Member States in building capacity in health ethics.