Background: Medicinal plants have been investigated for possible anti-cancer effects. The aim of the present study was to examine the cytotoxic activity of several medicinal native plants on different tumor cell lines. Methods: Plants including Salvia santolinifolia, Salvia eremophil, Salvia macrosiphon, Salvia reuterana, Teucrium persicum, Anvillea gracini and Francoeuria undulate were collected from different sites of Fars Province in southern Iran. The methanolic extracts of the plants were prepared and their effects at concentrations of 5-200 mu g/ml on various tumor cell lines were examined using a colorimetric assay. Results: Among the extracts of Salvia species, the strongest inhibitory effect was observed for S. reuterana extract. This extract showed a strong cytotoxic effect on the Raji lymphoma cell line. More than 50% of Raji cells growth was inhibited by 21 mu g/ml of this extract. S. macrosiphon extract also showed a strong inhibitory effect on this tumor cell line (IC50=77+/-1 mu g/ml). The greatest inhibitory effect of T. persicum extract was on Hela tumor cell line. This extract at concentration of 69+/-2 mu g/ml causes 50% inhibition of Hela cell growth. Corresponding data for A. gracini extract was obtained at concentrations of 83.5+/-2 and 86+/-3 mu g/ml on Jurkat and Hela cells, respectively. F. undulata reduced the proliferation of all the tumor cell lines used in this study but this inhibition did not reach 50%. Conclusion: All the extracts, more and less, showed inhibitory effects on the tumor cell lines. The most cytotoxic activity was observed in S. reuterana with an IC50 value less than 25 mu g/ml towards Raji cell line.