This paper presents the results of research on the effect of essential oils and ethanol extracts on the growth of mold fungi on Scots pine (Pinus sylvestris L.) wood. The analysis of fungal growth on the microbial medium showed that the degree of inhibition of microorganism growth depends on the amount of the extract added to the medium. At the same time, it was found that the highest dose of the extract, amounting to 5.0 cm3, almost completely inhibited the growth of fungi. In addition, it was found that mint ethanol extracts, the application of which in the wood is at least 40 g/m2, have a fungistatic effect at the initial stage of fungal development. Solutions of essential oils turned out to be more active against fungi, although also in this case the desired biocidal effect was not achieved. Essential oils significantly slowed down the growth of the fungus Ch. globosum, with the strongest fungistatic effect found for ‘Morocco’ spearmint oil (Mentha spicata L.). Despite the fact that in tests on agar-maltose medium, the strongest biocidal activity against Ch. globosum was found for spearmint ‘Crispa’ (Mentha spicata L.) oil, the effect of growth inhibition was not so clearly visible in studies on wood. Essential oils applied to the surface of the wood slowed down the growth of T. viride fungus, but not to the extent that it was found in the case of Ch. globosum. The qualitative and quantitative composition of substances belonging to the group of terpenes and their derivatives was characterized using the GCMS technique. It was shown that the ethanol extracts of mints were dominated by substances belonging to the oxygen-containing monoterpenoid and monoterpene groups. In terms of quality, the composition of essential oils turned out to be richer