Mycelial growth of some basidiomycetes in PDA medium containing bark polyphenols was evaluated. The addition of bark polyphenols accelerated the mycelial growth and affected the metabolite system remarkably in the case of the white-rot fungus Pleurotus ostreatus, which produced more than double the mycelial weight of the control. Laccase and acid protease activities increased with the increase of mycelial weight due to the addition of the polyphenols. In wood-meal medium containing bark polyphenols, mycelial growth of P. ostreatus increased rapidly but the yield of fruit bodies decreased with the increase of polyphenol concentration.