Isolation and identification of some potent anti-tumor compounds from medicinal plants has motivated researchers to screen different parts of plant species for the determination of anti-tumor effects. In this study, cytotoxic effects and IC 50 of specific concentrations of hydro-alcoholic extracts of fruits of Juniperus sabina and leaves of Zataria multiflora were compared with hydro-alcoholic extract of bark of Taxus baccata and Cisplatin, well-known anticancer compounds, on normal (CHO and rat fibroblast) and cancer (HepG2 and SKOV3) cell lines. The hydro-alcoholic extracts of the plants were prepared by percolation. The cytotoxic effects and IC 50 of the extracts on the cell lines were studied followed by colonogenic assay after 72 h incubation. The results showed that the extract of Juniperus sabina possesses lower IC 50 in comparison with Zataria multiflora extract on all 4 normal and cancer cell lines (P < 0.05); but, IC 50 of the Juniperus sabina extract was significantly higher than the Taxus baccata extract and Cisplatin on all 4 normal and cancer cell lines (P < 0.05). As a result, it is concluded that the extract of J. sabina has almost similar cytotoxicity with the extract of Taxus baccata on cancer cells.