The aim of the work was to investigate physico-chemical properties of lignomer by determination of - polystyrene content, - links between protection layer and wood, - wood tissue corrosion. The experimental material constituted sawdust of alder lignomer stored under laboratory conditions and in atmosphere of Cl*l2*s and HCl. Moreover, for comparison of occurring chemical and physical changes additional investigations on the sawdust of alder wood were performed. For selected chemical compounds leading to defractionation of basic substances of wood, lignomer maintains in 60per thousand in the solid phase. This proves the polystyrene protects well the wood tissue against chemical corrosion. Moreover, a great similarity of the spectrum of standard polystyrene to that contained in particular wood fractions eliminates the possibility of occurrence of distinct located chemical bonds.