Borderline personality disorder (BPD) is characterized by affective dysregulation and non-suicidal self-injurious behaviour (NSSI), which is closely linked with reduced pain perception. Several experimental studies revealed reduced pain sensitivity in BPD as well as significant correlations between pain perception, aversive inner tension and dissociation. Psychophysiological experiments revealed no deficit in the sensory-discriminative pain component in BPD. However, neurofunctional investigations point at alterations of the affective-motivational and the cognitive pain component in BPD. Preliminary evidence suggests that disturbed pain processing normalizes when patients stop NSSI after successful psychotherapeutic treatment. We could demonstrate that pain leads to a decrease in affective arousal and amygdala activity in patients with BPD and to an increase in amygdala-prefrontal connectivity. We are currently investigating the role of seeing blood and the importance of self-infliction of pain in the context of NSSI.