The characteristics of a stem cell are determined by being undifferentiated, auto renewable, and because of having the capacity of generating cells for multiple cellular lineages, with the capacity to proliferate indefinitely in cultures. The origin of the stem cells can be embryonic (blastomers and cells of the internal mass of the blastocyst) or somatic (pluripotential cells from adult tissues). The source of the somatic stem cells is the bone marrow, in which the hematopoietic stem cells and the mesenchymals (MSCs) are found. Diverse studies in animal models have demonstrated that MSCs constitute a potential tool for the establishment of regenerative therapies in injured tissues. This article reviews the properties of the stem cells, their potentials, their advantages and limitations in several animal models.