The object of the invention is a mixture of catechin and quercetin in a molar ratio varying between 3:1 and 6:1, respectively, for the treatment of the immunosuppression induced in the skin by aggressive agents such as airborne pollutants, dehydrating agents, ultraviolet radiation, and thermal and osmotic shocks, and a pharmaceutical, dermatological, nutritional or cosmetic composition containing said mixture as an active ingredient.
