The endometrium of the human uterus undergoes periodic shredding and renewal. Endometrium stem cells enable its regeneration. Some of them end up in menstrual blood during menstruation. It is possible to isolate them and grow them in culture. They are referred to as menstrual stem cells. Menstrual stem cells have mesenchymal and some embryonic markers. They do not present hematopoietic markers. If induced properly it is possible to obtain cell lines of all three germ layers. They show fibroblast-like morphology in vitro, stable karyotype even after a great number of passages, and high proliferative capacity. Because of these qualities, they have everything that is required for further studies as potential sources of cells for cell therapy, but what truly distinguishes them from other stem cells is the way they are collected. It is minimally invasive, economical, does not require surgery because donors perform it themselves, does not face ethical dilemmas, and results a great number of obtained cells. There are plenty of potential donors and the process can be repeated periodically. Dozens of papers on animal models have already been published on the use of menstrual stem cells treating various diseases, including premature ovarian dysfunction, diabetes type 1, and thin endometrium. The results are promising. The attitude of women towards the donation of menstrual blood is positive. All things considered; menstrual stem cells have all predispositions to enable great advance in regenerative medicine.