AbstractBackgroundRepetition of acute poisoning occurs frequently. The intention may change between episodes, many poisonings are treated outside hospitals, and few studies of repetition have taken this into account.AimsTo quantify the repetition frequency regardless of the level of healthcare (tiers) or the intention behind the poisoning, and to find possible risk factors for repetition.MethodA prospective multi-centre study of all acute poisonings in Oslo treated in hospitals, in an outpatient clinic, and by ambulance services. Repetition was estimated using Kaplan Meier calculations, and predictive factors were identified using Cox regression analysis.ResultsThe estimated one-year repetition rate was 29% (95%CI, 23 35%). Independent predictors for repetition were middle age (30 49 years), poisoning with opiates or sedatives, unemployment or living on social welfare, a previous suicide attempt, and a history of psychiatric treatment. Intention was not a significant predictor.ConclusionsRepetition of acute poisoning is high irrespective of the level of healthcare and the intention behind the poisoning.Declaration of interestNone. Funding is detailed in Acknowledgements.