Described is a method for treating wood, in which the wood is brought into contact with a mixture of liquid or water-soluble organic ammonium carboxylate and an active ingredient which repels invertebrates, characterized in that the organic ammonium carboxylate has the formula (1):[NR1R2R3R4]+n[R5(COO)n]−n (1),in which R1, R2 and R3 are selected from hydrogen, substituted and unsubstituted alkyls containing 1-6 carbon atoms, R4 is a substituted or unsubstituted alkyl containing 1-6 carbon atoms, R5 is hydrogen, a substituted or unsubstituted hydrocarbon containing 1-6 carbon atoms and n is an integral 1-6 and whereby wood-preservative active ingredient contains a chelating agent which repels invertebrate, which chelating agent is selected from an aminopolycarboxylic acid or a salt thereof, a hydroxy acid or a salt thereof or a phosphonate or a salt thereof or a mixture of chelating agents which belong to two of more groups thereof.
