This thesis explores early modem perceptions of menstrual bleeding, demonstrating that attempts to understand menstrual bleeding extended beyond the early modem medical world and captured the imagination of an entire cross-section of French society revealing culturally- embedded concerns about marriage, progeny, the family, patrilineage and state formation. The thesis draws on diverse sources including medical, casuistic and judicial texts, court records and private documents. Chapter One outlines the database of medical texts which forms a cornerstone of the thesis. The database includes texts printed between 1495, with the French edition of a medieval Latin work by Bernard de Gordon, and 1761, with Montpellier physician Jean Astruc's treatise on women's diseases which introduced the term 'menstruation' into French medical vocabulary. Chapter Two examines medical notions of menstrual bleeding within the context of attitudes to blood, blood-related fluids and the humoral and mechanical bodies. Sixteenth-century casuistic interpretations of Biblical taboos surrounding sex during menstrual bleeding and notions of menses as polluting are cross-referenced with medical notions of the relationship of menses to conception demonstrating the overriding concern for healthy progeny. Chapter Three explores the significance of concepts of time and periodicity, in the context of the merging of blood-related fluids in the humoral body, as a key to early modem perceptions of menstrual bleeding. Chapter Four examines early modern debates on the length of gestation and the calculation of a woman's time on the basis of the monthly menstrual cycle relating these to Sarah Hanley's model of the 'marital regime'. In Chapter Five, the ambivalent nature of menstrual bleeding in the medico-legal arena is investigated and the different cultural meanings ascribed to various bloody discharges emanating from the living female body are analysed. In the sixth and final chapter the role of menstrual bleeding in issues of sexual difference and hermaphroditism is discussed.