Abstract: The present invention relates to mustard extracts (Brassicaceae), in particular extracts of the Sinapis alba L. type and/or of the Sinapis arvensis L. type, and to active concentrates containing same and having potent tryptase inhibitory activity. These can be used for topical skin and scalp care applications in form of creams, lotions, gels, shampoos and the like, for the cosmetic treatment of the epidermal barrier. Barrier abnormalities and disruptions respectively are often the starting point of itching and inflammatory skin diseases.