Recent years have seen extensive debate about the future of drug laws in Ireland and the potential to stop criminalising people who are found to be in possession of illicit drugs for personal use. The recognition that change was possible and worth considering led to the establishment of the Citizens’ Assembly on Drugs Use which ran in 2023, reported in 2024 and was administered by the Department of An Taoiseach. The work of an Oireachtas Committee on Drugs Use, specially established to consider the Assembly’s recommendations, is, at the time of writing, soon to finish. However, despite decades of discussion and debate and reams of scientific research indicating the likely outcomes of different legal frameworks around the world, the best available evidence is too often sidelined or dismissed in our public and political conversations about legal change. This article seeks to provide answers to several recurring empirical and legal questions relating to the meaning and consequences of different frameworks. We outline how drug laws could change in Ireland and assess what the evidence says about the likeliest implications of different approaches. Our aim is to clarify these issues for Oireachtas members, health and justice policymakers and practitioners, and others who have questions about, or whose work touches on, this topic.