Phytolacacinoside A (1), a novel triterpenoid saponin, together with the seven known compounds, was isolated from 75% ethanol extract of the root of Phytolacca acinosa Roxb (Phytolaccaceae). Their structures were elucidated on the basis of analysis of spectroscopic data and physicochemical properties as 3-O-beta-[(beta-d-glucopyranosyl-(1 --> 4)-O-beta-D-xylopyranosyl)]-11beta-methoxy-jaligonic acid 30-methyl ester 28-O-beta-D-glucopyranoside (1), 3-O-beta-[(beta-D-glucopyranosyl-(1 --> 4)-O-beta-D-xylopyranosyl)]-jaligonic acid 30-methyl ester 28-O-beta-D-glucopyranoside (2, esculentoside G), 3-O-beta-[(beta-D-glucopyranosyl-(1 --> 4)-O-beta-D-xylopyranosyl)]-jaligonic acid 30-methyl ester (3, phytolaccoside E), 3-O-beta-D-xylopyranosyl-jaligonic acid 30-methyl ester (4, phytolaccoside B), hypaphorine (5), palmitic acid monoglyceride (6), beta-sitosterol (7), and daucosterol (8).