Compulsory licensing of patents provides governments, specially from developing and least-developed countries, with a powerful tool to promote easy and affordable access to essential medicines, vaccines and medical devices. Despite the legal possibility to issue such licenses has existed for over a century, it has been seldom used. While many reasons support that claim, the ‘regulatory chill’ caused by the prohibitive compensation sums granted by the ISDS mechanism has been brought to the public’s attention. As protected investments, measures affecting health-related IPRs might be in breach of the standards of treatment, international obligations assumed by States through IIAs. To begin, this article examines public health as a core element of the human right to health in international law, while considering the obstacles exerted by the international IP regime to allow access to essential medicines, vaccines and medical devices. Furthermore, it analyses the possibility to issue compulsory licenses over health-related IPRs and the tensions that it creates with the standards of treatment of international investment law, in particular, the prohibition of unlawful expropriation and Fair and Equitable Treatment. In the end, the case will be made for the States’ application of the ‘police powers’ doctrine as a general exoneration clause, by invoking international human rights law, and in particular, the human right to health.