The present invention relates to a composition for combating oxidation and alleviating the detrimental effects on skin caused by Asian Dust, the composition containing Melia azedarach bark and Nelumbo nucifera leaf extracts as a novel skin irritation alleviating agent. More specifically, the present invention contains Melia azedarach bark and Nelumbo nucifera leaf extracts, and entails: detoxification and expulsion of toxins by increasing the expression of NQO1 which is an enzyme that detoxifies toxins and of GSTT1 which is an enzyme that expels toxins; protection of the skin by increasing the expression of the skin antimicrobial peptide hBD3 which is a natural immune factor; and suppression of the production of active oxygen by increasing expression of the antioxidant proteins GPX1, catalase, Trx1 and Prdx1. Consequently, the invention has the advantages of skin protection and ageing suppression.