Extracts of roots of E. odoratum [ Chromolaena odorata ] (collected from Tinpipalay, Kabhrepalanchok District, Nepal, in November 2001) were fractionated using various organic solvents. The fractions so obtained were petroleum ether extract (F1), solid residue left after ethanol extraction (F2), liquid residue left after ethanol extraction (F3), hexane soluble sub-fraction of F2 (F2-1), dichloromethane- soluble sub-fraction of F2 (F2-2), ethyl acetate-soluble sub- fraction of F2 (F2-3), and 80% aqueous methanol soluble sub- fraction of F2 (F2-4). The root extract fractions were screened for such phytochemicals as sterols, triterpenoids, polyphenols, carbohydrates and reducing sugars, alkaloids, flavonoids, quinones, and tannins. These root extract fractions were further tested for their cytotoxicity in the brine shrimp ( Artemia salina ) lethality test. The LC₅₀ values indicated that F1, F2-1 and F2-2 were significantly cytotoxic against the brine shrimp nauplii. The fractions F3, F2-3 and F2-4 showed no cytotoxicity, whereas F2 was mildly cytotoxic in the brine shrimp lethality test.