OBJECTIVE: To investigate the phytochemicals and in vitro antioxidant,antimicrobial and cytotoxic potential of Rumex dentatus(R.dentatus)leaf extracts.METHODS: The total phenolics and flavonoids content of R.dentatus extracts were evaluated by the Folin-Ciocalteu and aluminum chloride colorimet-ric methods respectively.Antioxidant potential of studied plant extracts was assessed through 2,2-di-phenyl-1-picrylhydrazyl radical scavenging capacity,total reducing power and total antioxidant methods.Moreover,antibacterial and antifungal capacity was also evaluated by disc diffusion method against six clinically isolated multi-drug resistant bacterial strains as well as six fungal isolates.Further,cell cytotoxicity was also evaluated through 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazoli-um bromide assay.RESULTS: Ethanol extract showed highest total phenolic [(38.9 ± 1.5)μg gallic acid equivalent/mg] and total flavonoids [(17.2 ± 1.9)μg quercetin equivalent/mg] contents.Antioxidant assays indicated that ethanol and methanol extracts possess potent antioxidant potential.Moreover,it was observed that ethanol and hexane extracts have the potential to inhibit most of the tested multi-drug resistant bacterial strains while methanol,chloro-form and hexane extracts could inhibit the growth of pathogenic fungal strains successfully.Among all the studied extracts,ethanolic extract showed highest cytotoxicity against MCF-7 cell line then Hep-2 and DU-145 cell lines by MTT assay with low-est IC50 of 47.3 μg/mL.CONCLUSION: These results suggest that R.denta-tus could be a potent altative candidate for treatment of microbial infections and for breast cancer treatment.