The Mooncup is a menstrual cup that is an alternative to conventional sanitary protection. We aimed to determine whether the Mooncup is tolerated by asking 53 healthy female volunteers to record the frequency of changing sanitary protection and leakage over three menstrual cycles with regular sanitary protection and three cycles with the Mooncup. We measured the frequency of leakage and changing the Mooncup along with acceptability of the Mooncup. A total of 126 baseline cycles and 71 cycles with the Mooncup were recorded. The Mooncup leaked 0.5 times less frequently and required to be changed 2.8 times less frequently, on average, during one menstrual period than regular sanitary protection. Of the participants, 55% will carry on using the Mooncup for sanitary protection. Thus, we have concluded that, the Mooncup is acceptable for most women but could not be used for the objective measurement of menstrual blood loss because of the leakage that did occur.