An analysis of more than 50 million patient discharge records, published in BMJ Open, finds that legalization of recreational cannabis in the US is associated with a rise in hospital admissions for cardiovascular disease. The finding, covered by both medical and general-interest outlets, is described as the first to link recreational cannabis legalization to an increase in certain heart problems. As more states legalize, the research raises questions about how public-health systems should monitor and mitigate cardiovascular risks tied to increased cannabis use. The result is a reminder that legalization carries consequences that extend well beyond tax revenue and criminal justice.