Objective: Centella asiatica (L.) Urb. is a traditional Chinese medicine that has many medical applications, including wound healing and anti-oxidation. Some traditional Chinese Medicine doctors have found that it has therapeutic effects for external use in the repigmentation of vitiligo and post-inflammatory hypopigmentation. This study was designed to evaluate the effects of madecassoside, a major bioactive component of C. asiatica, on oxidative stress in human melanocytes and its possible mechanism of action.Methods: Normal human melanocytes were treated with 0.01 mmol/L H2O2 and various concentrations of madecassoside (0, 10, 50, 100 μg/mL). Subsequently, the retraction velocity of melanocyte dendrites was assessed. Determination of mitochondrial membrane potential (MMP, ΔΨm) was performed by flow cytometry and intracellular calcium ([Ca2+]i) levels were measured. Alterations of mitochondrial ultrastructure were observed by transmission electron microscopy (TEM). Acridine orange (AO) staining was used to measure autophagy. The LC3-II/LC3-I ratio, an indicator of autophagosome formation, was analyzed by Western blot.Results: Under H2O2-induced oxidative conditions, madecassoside inhibited melanocyte dendrite retraction, improved MMP and reduced the accumulation of [Ca2+]i in a concentration-dependent manner. Observations by TEM showed that madecassoside attenuated the damage of mitochondria in human melanocytes caused by oxidative stress. Furthermore, autophagy activation was demonstrated by AO staining and an increased LC3-Ⅱ/LC3-Ⅰ ratio.Conclusion: These results demonstrate the antioxidative effect of madecassoside on human melanocytes subjected to oxidative damage is activated by autophagy. Moreover, madecassoside could be a promising treatment for vitiligo mainly caused by oxidative stress.