Leviticus is one of the main written sources, along with texts by Aristotle (38422 bce) and Pliny the Elder (23-79 ce), credited with the origin of negative attitudes towards menstruation and menstrual fluid in the Judaeo-Christian world.1 Anxieties about sex during menstruation suggest some overlap between these traditions, although Aristotle’s and Pliny’s texts explicitly mention the negative properties of menstrual fluid, while Leviticus does not. Leviticus prohibits sex during menstruation, whereas Pliny’s Natural History (c.77-79 ce) warned of the nefarious consequences of such an act ‘for the woman’s sexual partner, and progeny’, cautioning that ‘coitus [with a menstruating woman] is fatal for men’.2 In Leviticus, however, it is a question of ritual or spiritual, rather than physical, impurity that is contracted during contact, sexual or otherwise, with a menstruant.