Two new triterpenoids, 2alpha-hydroxy-3beta-O-acetyllup-20(29)-en-28-oic acid (1) and 3- O-(4'- O-acetyl)-alpha- L-arabinopyranosyloleanolic acid ( 2), together with two known triterpenoids, betulinic acid ( 3) and messagenic acid ( 4) were isolated from the CHCl3 extract of Garcinia hanburyi resin. The structures were elucidated by analysis of the NMR spectroscopic data. The antiproliferative effects and the apoptosis induction abilities of compounds 1 and 2 were determined in four human leukemia cell lines. Compound 2 was more potent than compound 1 in inhibiting cell growth with IC50 values of 2.45, 2.69, 2.42, and 4.15 microM in HL-60, NB4, U937 and K562 cells, respectively.