Background: Psychedelic drugs are increasingly visible in society once more, but their risks and adverse effects have received less attention than perhaps they should. While fatalities associated with psychedelics appear rare, a systematic approach to characterising their aetiology is required to inform harm minimisation efforts. Aims: This study aimed to analyse prevalence and characteristics of psychedelic-related deaths in England, Wales, and Northern Ireland, between 1997 and 2022. Methods: We analysed coroner reports submitted to the National Programme on Substance Use Mortality where psychedelic serotonergic agonist drugs were involved in the death, and conducted a thematic framework analysis to explore potential factors associated with their occurrence. Results: We identified 28 cases where psychedelics were implicated (75 %, N = 21) or potentially implicated (25 %, N = 7) in the death; 19 of these involving psychedelic tryptamines (LSD 39 %, N = 11; Psilocybin 21 %, N = 6; DMT 7 %, N = 2), and 9 psychedelic phenethylamines (incl. NBOMes 18 %, N = 5). Most deaths were deemed accidental by the coroner (86 %, N = 24), including both traumatic injuries and drug toxicities; most cases involved multiple implicated drugs (68 %, N = 19); and most of the deceased were under 30 years of age (82 %, N = 23). Thematic framework analysis identified nine themes in the deaths across three categories. 'Polysubstance use' was the most common theme (82 % of cases, N = 23/28), followed by a suboptimal 'physical environment' (70 % of cases where this information was available, N = 14/20). Conclusions: The profound and often unpredictable effects of psychedelics pose a unique profile of risks and adverse reactions. Nevertheless, psychedelic-related deaths remain very rare in comparison to other recreational drugs, and frequently involve polydrug use. Implications for harm reduction and policy are discussed.