Besides three known compounds, momordines I (4), Ib (3) and -spinasterol-3-B-D- glucopyranoside (2), a new momordic acid (1) was isolated from the root of Vietnamese Momordica cochinchinensis. The chemical structures of 1-4 were elucidated by interpretation of one- and two-dimensional nuclear magnetic resonance spectra (DEPT, COSY, HMQC and HMBC).