Experiments in vivo demonstrated the protective effect of modified nanodiamonds on guinea pig skin after local exposure cobalt ions, but not chrome ions. The observed differences are determined by different adsorption of these ions by nanodiamonds: in vitro experiments showed that nanodiamonds adsorbed cobalt ions, but not chrome ions from water solutions. The perspectives of using modified nanodiamonds as a new adsorbent for prevention of allergic contact dermatitis induced by ions of bivalent metals are discussed.