The administration of antioxidants has been shown to enhance repair and healing processes in cutaneous tissue. Silymarin, an extract from Silybum marianum has been reported to be beneficial in the treatment of chemically-induced oxidative stress in mouse. In this study, we investigated the protective effects of silymarin, its flavonolignans silybin and dehydrosilybin and flavonoids quercetin and taxifolin against hydrogen peroxide-induced damage to human keratinocytes and mouse fibroblasts. The results showed that the cytotoxicity of hydrogen peroxide was dose-dependent in both cell lines. Pre-treatment with test compounds decreased oxidative injury. Dehydrosilybin and quercetin were the most powerful protectants. Silymarin was comparable to silybinin, its main component. This correlates with the antioxidant potential of the compounds. Our findings suggest that silymarin, flavonolignans and flavonoids may be useful as agents for improving skin tissue regeneration.