ABSTRACT:Heracleum platytaenium is an edible herb and strongly aromatic plant that is endemic to Turkey. Although, a number of studies have been conducted on the components and composition of essential oils of the different parts of this species, its antioxidant, antiproliferative and /or cytotoxic proporties have never been explored. The present study aimed to evaluate total phenolic content (TPC), total flavonoid content (TFC), the antioxidant activity and anticancer properties of the methanolic extracts of H. platytaenium. The results showed that the total phenolic and flavonoid contents were found to be higher in the methanolic extracts from the flowers of the plant. The methanolic flower extract of H. platytaenium scavenged about 86% and stem extract of H. platytaenium scavenged about 83% of free DPPH radicals. The best inhibitory profile for GST was observed with the methanolic extract of the plant from flowers. In addition, the methanol extract of H. platytaenium from the stem increased GPx activity with the 1.25 mg/mg plant extract. The maximum dose of the flower and stem extracts of the plant inhibited 10 % and 8% CAT activity. Then, MTT assay was used for the study of the cytotoxic effect of the plant extracts. Both methanolic flower and stem extract of H. platytaenium showed moderate anticancer effect on T47-D cell lines, but no cytotoxic effect was observed on MDA-MB-231 cells. In conclusion, methanolic extracts of H. platytaenium flower and stem showed apparent antioxidant and cytotoxic effects leading the way for their potential use as food additives to help to fight against the growth and spreading of cancerous cells. However, for a definitive conclusion, further studies on other cell lines as well as animal models and subsequent clinical studies are warranted.