Four novel octanorcucurbitane triterpenes, octanorcucurbitacins A—D (1—4), together with one known octanorcucurbitane triterpene, kuguacin M (5), were isolated from the methyl alcohol extract of the stems of Momordica charantia . Their structures were elucidated on the basis of extensive spectroscopic analyses. Compound 3 inhibited tert -butyl hydroperoxide ( t -BHP)-induced hepatotoxicity against HepG2 cells.