Plants-derived chemical constituents have been potentially used in cancers therapy, which are safer than chemotherapy. Apoptosis is a cellular process of defined programmed cell death that is of tremendous interest to study and treat cancer. In the present study, the antioxidants activities of red cabbage leaves and broccoli florets (Brassica vegetables) extracts and their apoptotic effects on colorectal cancer cell lines (CaCO2) were investigated. Antioxidants properties of the aqueous methanolic extracts were addressed through determining total phenolics, flavonoids, total antioxidant capacities and DPPH scavenging activities. Then, anticancer properties were assessed by determining the inhibitory concentrations that kill 50% of CaCO2 using MTT assay. To investigate the apoptotic effects of the extracts, gene expression analysis using real time polymerase chain reaction (RT-PCR) of Bax, caspase 3 and Bcl2 genes was done. The results showed that red cabbage and broccoli extracts exhibited powerful antioxidant activities. Furthermore, these extracts induce apoptosis in CaCO2 cells by upregulating Bax and caspase 3 and downregulating Bcl2 genes. In conclusion, red cabbage extract showed strong antioxidant activities more than broccoli extract, while broccoli inhibit proliferation of colon cancer cells by promoting apoptosis more than red cabbage done. Cruciferous vegetables contain important substances targeting apoptosis in CaCO2 cell lines that can significantly inhibit colon cancer growth.