The Teucrium persicum plant belongs to the Teucrium genus and belongs to the Lamiaceae family, one of the native plants of Iran, which grows in Fars province. This plant has been used in traditional Iranian medicine for the treatment of headache and abdominal pain for many years. In this study, we investigated the cytotoxic effects of ethyl acetate extract of T. persicum plant on breast cancer cells (MCF-7). First, the chemical profile of T. persicum ethyl acetate extract was investigated by GC/MS test. The most abundant compounds identified in the extract were eicosane (an alkane), carnosic acid (a phenolic compound also known as salvin), and alpha- and delta-cadinene (sequoterpenoid alcohols). Then MCF-7 cells were treated with different concentrations of extract for 48 hours. The results of MTT tests showed that the IC50 of T. persicum plant extract is about 50 µg/ml. After treating MCF-7 cells with concentrations of 50 and 100 μg/ml extract for 48 hours, the nuclei of the cells were stained with DAPI and examined using a fluorescent microscope. Microscopic observations showed that in the cells treated with the extract, the chromatin was condensed and the nucleus was fragmented, these changes were not observed in the nucleus of the control cells. Our results showed that ethyl acetate extract of T. persicum can cause cell death by activating apoptosis.