AIM: To evaluate the antioxidant activity of naringenin in human retinal pigment epithelium(ARPE-19) cells and human umbilical vein endothelial cells (HUVEC). METHODS: MTT assay was used to measure the viability and proliferation of ARPE-19 cells and HUVEC. RESULTS: Three and 10mg/L naringenin significantly increased the proliferation of ARPE-19 cells by 10.8% and 11.4%, respectively. Ten mg/L naringenin increased hypoxia-, 0.3mmol/L NaN₃^-, and 200umol/L H₂O₂ -induced damage of ARPE-19 cells by 55.2%, 69.2%, and 50.3%, respectively. One mg/L naringenin increased the viability of 50umol/L t-BHP-, and 30mg/L NaIO₃-treated ARPE-19 cells by 20.2% and 30.4% , respectively. Thirty mg/L naringenin also increased the proliferation of 50umol/L t-BHP-treated ARPE- 19 cells by 32.2%, and 1mg/L naringenin increased the proliferation of 30, 100 and 300mg/L NaIO₃-treated ARPE-19 cells by 30.3% , 10.3% and 18.5% , respectively. The reduction of HUVEC was 23.9%, 70.4% and 77.9% in the 3, 10 and 30mg/L naringenin-treated groups, respectively. Furthermore, 1 and 3mg/L naringenin increased hypoxiainduced damage in HUVEC by 10.7% and 13.1% , and 300mg/L NaIO₃-induced damage in HUVEC by 41.2% and 37.7%. Three mg/L naringenin increased 200 and 400umol/L H2O2-in-jured HUVEC by 20.1%and 21.5%, respectively. CONCLUSION: Naringenin increases the proliferation of ARPE-19 cells and inhibits the growth of HUVEC, and has potent antioxidant activity in ARPE-19 cells and HUVEC.