Background: Having non-toxic anticancer agents are targeted by researcher in the biomedical field around the world. Cancer-fighting phytochemicals have been potentially identified in several medicinal plants for cancers therapy. Apoptosis paid a great promise to study mechanism of cancer treatment. Objectives: This study aimed to investigate the antioxidants activities of the aqueous ethanolic extract of sweet red pepper (Capsicum Spp.) and its effects on colorectal cancer cell lines (CaCO-2). Methods: Phytochemical constituents and anticancer efficacy of sweet red pepper extract were evaluated. The apoptotic mechanism of the extract was proved by using real time polymerase chain reaction (RT-PCR) for apoptotic related genes (Bax, caspase 3 and Bcl-2). Results: The results showed that sweet red pepper extracts exhibited powerful antioxidant activities. Moreover, this extract could trigger apoptosis in human colorectal tumor cells by overexpressing apoptotic genes (Bax and caspase 3) and down-expressing the anti-apoptotic Bcl-2 genes. Conclusion: The sweet red pepper extract could inhibit CaCO-2 cellular proliferation by inducing apoptosis due to their phytochemical contents.