The present study investigated the chemical constituents of the roots and rhizomes of Panax notoginseng. Compounds were isolated by various column chromatographic methods, and their structures were elucidated by the extensive analysis of spectroscopic data and chemical evidences. A novel 12, 23-epoxy dammarane-type saponin, named epoxynotoginsenoside A (1), together with four known compounds (2-5), was isolated and characterized.