Abstract: AIM:To examine the effect of berberine on hypoxia reoxygenationinduced apoptosis in myocardial cells and to explore the potential mechanisms involved. METHODS: H9C2 cardiac muscle cells were divided into: normal control group (NC group), simple berberine group (BR group), hypoxia/reoxygenation group (H/R group) and drug treatment group (divided into LBR group: 1.5×10-6 mol/L, HBR group 1.5×10-4 mol/L). Myocardial cell vitality was detected by MTT, nucleus morphological changes were examined using Hoechst 33258 dye and cytochrome-C and caspase-9 protein expressions were detected by Western blot. RESULTS: Compared with that in the NC group, simple berberine exerted no effect on myocardial cells in the BR group. Compared with those in the H/R group, cell vitality in treatment groups increased and apoptosis decreased significantly. Western blot results showed that berberine inhibited the expressions of apoptosis related proteins cytochrome-C and caspase-9. CONCLUSION: Berberine has a significant protective effect on hypoxia reoxygenation induced apoptosis in myocardial cells possibly by inhibiting the release of cytochrome-C and decreasing the expression of caspase-9.