In this report, UNAIDS shows what works to reduce the impact of HIV and other harms related to drug use. Countries that have moved away from laws and policies that are harmful to people who use drugs and that have increased investment in harm reduction have reduced new HIV infections and improved health outcomes. These policies also deliver broader social benefits, such as lower levels of drug-related crime and reduced pressure on health-care and criminal justice systems. However, despite the large body of scientific evidence, these approaches are far from universal. Millions of people who use or inject drugs continue to be criminalized and marginalized. Stigma and discrimination prevent their access to health care, harm reduction and legal services. Levels of drug use remain unchanged. UNAIDS therefore calls for the global adoption of a people-centred, public health and human rights-based approach to drug use.