The global transmission of infectious diseases has fuelled the need for a more developed legal framework in international public health to provide prompt and specific guidance during a large-scale emergency. This book develops a means for States to take advantage of the flexibilities of compulsory licensing in the Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS), which promotes access to medicines in a public health emergency. It presents the precautionary approach (PA) and the structure of risk analysis as a means to build a workable reading of TRIPS and to help States embody the flexibilities of intellectual property (IP). The work investigates the complementary roles of the World Health Organization (WHO) and the World Trade Organization (WTO) in order to promote the harmonisation of the precautionary approach in relation to the patenting of crucial pharmaceutical products. By bringing together international trade law and intellectual property law Phoebe Li demonstrates how through the use of risk analysis and the precautionary approach, States can still comply with their legal obligations in international law, while exercising their sovereignty right in issuing a compulsory licence of a drug patent in an uncertain public health emergency. This book will be of great interest to students and academics of medical and healthcare law, intellectual property law, international trade law, and human rights law.