A composition for retarding skin aging which contains an edible herb medicine or medicines round in Taiwan, in particular a plant extract or extracts having melanin formation-unhibiting, elastase-inhibiting, hyaluronidase-inhibiting, active oxygen-eliminating and/or radical-capturing type antioxidant activities, and a medicinally acceptable base and/or additives for external dermal application. The composition is useful in promoting skin whitening effects, maintaining the tension and elasticity of the skin, facilitating skin moistening and providing the skin with anti-inflammatory and/or anti-allergic properties.