Objectives : Lonicerae Japonicae Flos (LJF) has been shown anti-oxidant, anti-inflammatory, anti-viral, anti-rheumatoid properties. However, it is still largely unknown whether LJF inhibits skin injury against oxidative stress in human keratin ocyte, HaCaT cells. The purpose of this study was to evaluate the protective effects of LJF against hydrogen peroxide(H2O2)-induced oxidative stress in human keratinocytes, HaCaT cells. Methods : To evaluate out the protective effects of LJF on oxidative inju ry in HaCaT cells, an oxidative stress model of HaCaT cells was established under a suitable concentration (500 µM) hydrogen peroxide. HaCaT keratinocyte cells were pre-treated with LJF (0.1, 0.25 or 0.5 mg/ml), and then stimulated with H2O2. Then, the cells were harvested to measure the cell viability, DNA damage, and release of reactive oxygen species (ROS). Results : LJF (0.1, 0.25 or 0.5 mg/ml) itself did not show any significant toxicity in HaCaT cells. The treatment of H2O2 caused the oxidative stress, leading to the cell death, and DNA injury. However, pretreatment with LJF reduced cell death, and DNA injury. The stimulation of H2O2 on HaCaT cells resulted in excessive release of ROS, which is the main factor of oxidative stress. The excessive release of ROS was inhibited by LJF treatment significantly. Conclusions : These results could suggest that LJF exhibited the protective effects of HaCaT cells against H2O2 -induced oxidative stress by inhibiting ROS release. It could be explained that LJF inhibit skin damages against oxidative stress. Thus, LJF would be useful for the dev elopment of drug or cosmetics treating skin troubles.