In this paper the surface condition of jeweller's metallic material covered by nanostructured carbon layer after the in vitro model test was investigated. The phenomenon of body modification has made that the most popular and the most often applied is jewellery made of metals like stainless steel, titanium and its alloys. However these kinds of metals are not safe and can cause health complications. Biocompatible carbon coatings were used in order to exclude the side effects of metallic jewellery use. Body modification trend is popular among youth to a large degree--they who are always looking for the cheap decorations. Taking this fact into consideration the jewellery made of stainless steel, which is used the most often was exposed to modification by carbon coating. Two methods of plasma activated chemical vapour deposition (PA CVD) were used for the carbon coatings production purpose: radio frequency (RF) and microwave/radio frequency (MW/RF). In order to point the best parameters of these coatings manufacture processes, examinations of physiochemical properties and analysis of surface topography (optical microscopy, scanning electron microscopy with X-ray microanalysis) were made. So modified jewellery was investigated in in vitro model as regards resistance to the biological environment and coatings stability as well. The conducted examinations showed that modifications of decorations made of 316L stainless steel by carbon coatings allow for the creation of biocompatible, non-toxic jewellery. Tests showed that human fibroblasts grow and keep vitality in a presence of jewellery covered by carbon coating, whereas die very fast sticking the non-modified surfaces of decorations. The carbon coating constitutes a barrier which isolates jewellery from the surrounding environment and simultaneously contacts with it in a safe way.