Crude extracts or phytochemicals obtained from some plants have potential anti-cancer properties. Teucrium persicumis an Iranian endemic plant belonging to the Lamiaceaefamily which has traditionally been used to relieve abdominal pains. However, the anti-cancer properties of this species of the Teucriumgenus have not been investigated previously. In this study, we have used a highly invasive prostate cancer cell line, PC-3, which is an appropriate cell system to study anti-tumor properties of plants. A methanolic extract obtained from T persicumpotently inhibited viability of PC-3 cells. The viability of SW480 colon and T47D breast cancer cells was also significantly decreased in the presence of the T persicumextract. Flow cytometry suggested that the reduction of cell viability was due to induction of apoptosis. In addition, the results of wound healing and gelatin zymography experiments supported anti-cell invasion activity of T persicum. Interestingly, sublethal concentrations of T persicumextract induced an epithelial-like morphology in a subpopulation of cells with an increase in E-Cadherin and β-Catenin protein levels at the cell membrane. These results strongly suggest that T persicumis a plant with very potent anti-tumor activity