The International Harm Reduction Association (IHRA) has launched the fifth in a series of online document collections – this time focusing on the extent and prevention of overdose. This collection is designed to improve knowledge and discussion on the important topic of overdose. It is the result of several months of literature searches and research by IHRA – inspired by the Eurasian Harm Reduction Network (EHRN) – with the guidance of an International Reference Panel. Overdose is a risk for all psychoactive drug users, but is a fundamentally preventable harm. In many ways, overdose prevention is a quintessential harm reduction approach. View the collection here.