This present study aimed to elucidate antiproliferative activity of four extracts (CHCl(3), EtOAc, n-BuOH and H(2)O) and chemical constituents isolated from the most potent extract of Tetrastigma hemsleyanum Diels et. Gilg (TDG) against MDA-MB-435S cell lines using the MTT assay at various concentrations in vitro. Ten compounds were isolated and identified as (1) β-sitosterol, (2) palmitic acid, (3) protocatechuic acid, (4) salicylic acid, (5) p-hydroxybenzoic acid, (6) resveratrol, (7) trans-4-hydroxycinnamic acid, (8) kaempferol, (9) quercetin, and (10) isoquercitrin. Compounds 3, 5-7, 10 were the first report of isolation from this plant. Moreover, antiproliferative activity displayed that the CHCl(3), H(2)O extracts and compounds 6, 8 exhibited obvious inhibitory effects on MDA-MB-435S cell lines with IC(50) values 100.28± 2.64, 127.48±3.45, 92.39±1.68 and 120.30±1.97μ/mL, respectively. Thus the obtained results indicate antiproliferative activity of TDG against MDA-MB-435S cell lines is ascribable to the most potent CHCl(3) extract along with active compounds 6 and 8, which could be considered as a potential chemotherapeutic agent in breast cancer.