Menstruation is an impolite topic: often avoided in both everyday conversation and academic journals. This article expands the limited historiography on the subject by investigating a pivotal moment in the Australian history of menstruation: 1940-1970. By exploring sex education texts and menstrual product advertisements alongside oral history accounts, the paper reveals that the middle decades of the twentieth century were a time when the ideologies and technologies of menstruation were transformed. Australian girls were encouraged to reject older messages about incapacity at ‘that time of the month’ and embrace a full range of activities , armed with the much-lauded protection offered by disposable, commercially-produced pads and tampons. This article engages in transnational debates about this modernisation of menstruation, asking: have Australian women and girls been liberated by these changes to participate more fully in the public sphere, or have they become enslaved to a more rigorous set of hygienic expectations?