This thesis focuses on the significance of blood and the perception of the body in both learned and popular culture in order to investigate problems of identity and social exclusion in early modern Europe. Starting from the view of blood as a liminal matter, manifesting fertile, positive aspects in conjunction with dangerous, negative ones, I show how it was believed to attract supernatural forces within the natural world. It could empower or pollute, restore health or waste corporeal and spiritual existence. While this theme has been studied in a medieval religious context and by anthropologists, its relevance during the early modern period has not been explored. I argue that, considering the impact of the Reformation on people’s mentalities, studying the way in which ideas regarding blood and the body changed from late medieval times to the eighteenth century can provide new insights about patterns of social and religious tensions, such as the witch-trials and persecutions. In this regard the thesis engages with anthropological theories, comparing the dialectic between blood and body with that between identity and society, demonstrating that they both spread from the conflict of life with death, leading to the social embodiment or to the rejection of an individual. A comparative approach is also employed to analyze blood symbolism in Protestant and Catholic countries, and to discuss how beliefs were influenced by both cultural similarities and religious differences. Combining historical sources, such as witches’ confessions, with appropriate examples from anthropology I also examine a corpus of popular ideas, which resisted to theological and learned notions or slowly merged with them. Blood had different meanings for different sections of society, embodying both the physical struggle for life and the spiritual value of the Christian soul. Chapters 2, 3 and 4 develop the dualism of the fluid in late medieval and early modern ritual murder accusations against Jews, European witchcraft and supernatural beliefs and in the medical and philosophical knowledge, while chapters 5 and 6 focus on blood themes in Protestant England and in Counter-Reformation Italy. Through the examination of blood in these contexts I hope to demonstrate that contrasting feelings, fears and beliefs related to dangerous or extraordinary individuals, such as Jews, witches, and Catholic saints, but also superhuman beings such as fairies, vampires and werewolves, were rooted in the perception of the body as an unstable substance, that was at the base of ethnic, religious and gender stereotypes.