Many phytochemicals have been recognized to have potential chemopreventive or chemotherapeutic efficacy in cancer treatment. In this study, we hypothesized that berberine would have anticancer activities in SCC-4 human tongue cancer cells. Results indicated that berberine reduced the viability of SCC-4 cells, which was initiated by the generation of reactive oxygen species, via an increase in cytosolic Ca(2+). Berberine-induced apoptosis was associated with a reduction of the mitochondrial membrane potential associated with changes in the Bax/Bcl-2 ratio, release of cytochrome c from mitochondria and activation of down stream caspase-3. Real-time PCR showed that berberine stimulated gene expression of caspase-8, -9 and -3, apoptosis-inducing factor and endonuclease G. The present study demonstrated that berberine-mediated apoptosis of SCC-4 cells is regulated by ROS, mitochondria, caspase-3-dependent and mitochondria-dependent pathways, suggesting that berberine may be considered for future studies as a promising therapeutic candidate for human tongue cancer.