Pholiota gummosa, Pholiota squarrosa, Kuehneromyces mutabilis, Pleurotus ostreatus. Amino acids - Aqueous and methanol extracts obtained from fruiting bodies of lignicolous basidiomycete mushrooms Pholiota squarrosa, Pholiota gummosa, Kühneromyces mutabilis, Pleurotus ostreatus and Armillaria mellea (Basidiomycetes) have been studied for content of free sugars, free amino acids, phenolic acids, fungal toxins, glycosides, alkaloids and nitrogen compounds. Thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and qualitative chemical reactions have been used. Phenolic acids (4-hydroxybenzoic, 4-hydroxycinnamic, 4-hydroxy-3-methoxybenzoic, and 3,4-dihydroxyphenylacetic), free amino acids (alanine, valine, serine, proline, methionine, asparagine), cortinarin A, steroid glycosides and choline were mostly observed within tested species. Free sugars, particularly glucose, arabinose, fructose, galactose, rhamnose, and sucrose have not been observed by our methods. The obtained data indicated the presence of biological active substances, such as phenolic acids, choline, and steroid glycosides in analysed mushroom samples.