Psilocybin-containing mushrooms have emerged as promising therapeutic tools for depression and other psychiatric disorders. This project aims to investigate whether gut microbiota-derived metabolites and epigenetic regulation contribute to the therapeutic actions of psilocybin and Psilocybe-derived products. Building upon a completed in vivo study in Wistar Han rats, faecal, plasma and brain samples will be analysed using complementary metabolomic and epigenetic approaches. Untargeted GC-MS and NMR metabolomics will be used to identify microbiota-related and systemic metabolic signatures induced by pure psilocybin and Psilocybe cubensis extract. Brain tissues will be analysed to assess DNA methylation and histone-related modifications in pathways associated with neuroplasticity, stress response, neuroinflammation and serotonergic signalling. The integration of behavioural, metabolomic, microbiome, epigenetic and pharmacodynamic data will provide a comprehensive understanding of the mechanisms underlying the prolonged effects of psilocybin and identify novel therapeutic targets and biomarkers relevant to psychedelic-assisted therapies.