The chemical constituents and cytotoxic activities of roots of Cissus javana (Vitaceae),a medicinal plant used to treat tumors in Myanmar traditional system,were studied.Nineteen compounds were isolated by chromatographic techniques and elucidated based on spectroscopic data and comparison with reported data from ethanolic extract.These compounds were identified as 2-C-β-D-glucopyranosyl-3,5-dihydroxy-4-methoxy-benzoic acid (1),picraquassioside D (2),2-O-β-D-glucopyranosyloxy-4,6-dihydroxyisovalerophenone (3),bergenin (4),(-)-ampelopsin A (5),(-)-epicatechin (6),(-)-epiafzelechin (7),(E)-resveratrol (8),4-O-(2-hydroxy-1-hydroxymethylethyl)-dihydroconiferyl alcohol (9),25-hydroperoxycycloart-23-en-3β-ol (10),lupeol (11),δ-amyrin (12),palmarumycin SA1 (13),(3R)-palmarumycin BG1 (14),(6R,9S)-roseoside (15),(-)-lyoniresinol-2a-O-β-D-glucopyranoside (16),(-)-lyoniresinol-3a-O-β-D-glucopyranoside (17),(+)-isolarisiresinol-3a-O-β-D-glucopyranoside (18),and (+)-lyoniresinol-3a-O-β-D-glucopyranoside (19),respectively.Compounds 1-4,13,and 14 are phenols;5 and 8 are stilbenes;6 and 7 are flavanols;9 is a phenylpropanoid,10-12 are triterpenoids;15 is a sesquiterpenoid glucoside;16-19 are lignan glucosides.Compounds 1-3,5-7,9,10,and 13-19 were isolated from Cissus genus for the first time.The ethanolic extract of Cissus javana roots showed good cytotoxic activity against human rectal cancer SW480 cell line with an IC₅₀ value of 15.12 μg/mL.Compound 10 showed potent cytotoxic activities against human leukemia HL-60 cell line and human rectal cancer SW480 cell line,with IC₅₀ values of 12.97±0.69 and 21.08±0.70 μM,respectively.This research reported the chemical constitutes of C. javana roots for the first time;it provided evidence for cytotoxic activities of C. javana,which comply with the traditional use for antitumor in Myanmar.