The article presents a pilot study based on intervention conducted in Croatia in 2022. Despite intensive peacebuilding efforts, ethnic tensions in post-conflict societies remain high, suggesting that current strategies may be missing critical components. This experiment integrated recent neurophysiological findings, particularly polyvagal theory, into peacebuilding intervention. The intervention involved a two-day seminar in Zagreb, where trauma-informed, body-based techniques were used to address post-war trauma. Participants learnt to recognise and manage trauma reactions by promoting their interoceptive awareness and a felt sense of safety. The seminar included both theoretical and experiential components, focusing on the impact of trauma on the autonomous nervous system and interpersonal dynamics. The study used an experimental design with intervention and control group to investigate the effects of the seminar. Measures included interoceptive awareness, autonomic reactivity, ethnic distance, perspective taking and mental well-being. The results showed that the participants in the intervention group showed significant improvements in interoceptive awareness, particularly in not worrying and emotional awareness subscales compared to the control group. However, ethnic distance scores did not decrease as expected, highlighting the complexity of changing deep-rooted attitudes. The study faced some challenges, including participant recruitment and the short duration of the intervention, which may have limited its effectiveness. Despite these limitations, the findings suggest that integrating trauma-informed approaches into peacebuilding efforts holds promise for improving interethnic relations. Future research should focus on longer interventions and diverse participant groups to better understand the potential of these methods in various contexts.