cells exhibited chromatin condensation (an apoptotic characteristic). HCT increased reactive oxygen species (ROS) production and decreased the mitochondrial membrane potential (ΔΨ(m)) in examined cells. Moitchondria-dependent apoptotic signaling pathway was shown to be involved as determined by increase in the levels of cytochrome c, Apaf-1, and caspase-3 and -9. The decrease in the level of ΔΨ(m) was associated with an increase in the BAX/BCL-2 ratio which led to activation of caspase-9 and -3. Based on our results, HCT induced apoptotic cell death in human primary colorectal cancer cells through a mitochondria-dependent signaling pathway was shown to be involved as determinted by increase in the levels of cytochrome c,Apaf-1,and caspase-3 and-9