3′-Hydroxypterostilbene (3′-HPT) is one of the active constituents of Sphaerophysa salsula and Pterocarpus marsupium which may be useful in treating different types of haematological malignancies. 3′-Hydroxypterostilbene, a natural pterostilbene analogue, effectively inhibits the growth of human colon cancer cells (IC50s of 9.0, 40.2, and 70.9 µM for COLO 205, HCT-116, and HT-29 cells, respectively) by inducing apoptosis and autophagy. 3′-Hydroxypterostilbene inhibits the PI3K/Akt/mTOR/p70S6K, and p38MAPK pathways and activates the ERK1/2, JNK1/2 MAPK pathways.