Nisin is a polycyclic peptide containing 34 amino acids produced by Lactococcus lactis during fermentation. Recently, researchers considered nisin as an anticancer peptide. Herein, the authors aim to evaluate the nisin effects on the apoptosis stimulation in the colon cancer cell line. The SW480 cells were exposed to discrepant concentrations of nisin and the cell viability as well as the expression of bcl-2 and bax genes and proteins were surveyed by the MTT assay, Real-Time PCR and western blotting method, respectively. Furthermore, the Ethidium bromide/Acridine orange staining was performed to visualize apoptotic cells. 4000, 3000, 2500 and 2000 μg/ml of nisin led to significant anti-proliferative impact and augmentation apoptotic index (bax/bcl-2 ratio) both at mRNA and protein levels (p < 0.05). Furthermore, the apoptotic impacts were demonstrated after Ethidium bromide/Acridine orange (EB/AO) staining to have a dose dependent manner. Our outcome suggested that nisin could induce apoptosis via intrinsic pathways and lead to cancerous cell death. •Nisin as the known bacteriocin demonstrates the cytotoxic effects on the colorectal cancer cell line.•The cytotoxic impact of nisin was performed via the intrinsic apoptotic pathway.•Nisin is able to increase apoptotic index (bax/bcl-2) in the cancer cells.