The present work intends to illustrate problems linked to wood conservation and protection in the case of biological attack. The experimentation regards effects produced by white and brown rot, on White poplar (Populus alba) and Fir spruce (Picea abies), treated with two consolidants, Paraloid B72 and Regalrez 1126, both applied individually as well as together, with the aim of obtaining a different level of penetration in the wood. The aim was to test whether these products, wich are generally applied during restoration, can have biocid actions on healthy wood, evaluating changes both on a morphological and chemical level induced by fungus attack, analysing susceptibility to biological colonisation and testing protective efficacy. The obtained results for Fir spruce showed how different penetration of the two type of consolidands favoured selective development of only one of the two rots, slowing down, but not blocking, biological growth. On White poplar samples both consolidants showed, over all, a good protective efficacy