Described is a method and a composition for preparing wood, to its use and to the wooden product obtained by the method. The method and the composition use liquid or water-soluble organic ammonium carboxylate of formula (1): [NR1R2R3R4]+n[R5(COO)n]−n (1), in which R1, R2 and R3 are selected from hydrogen, substituted alkyls containing 1-6 carbon atoms and unsubstituted alkyls containing 1-6 carbon atoms, R4 is a substituted alkyl or an unsubstituted alkyl containing 1-6 carbon atoms, R5 is hydrogen, a substituted hydrocarbyl containing 1-6 carbon atoms or an unsubstituted hydrocarbyl containing 1-6 carbon atoms, and n is an integer 1-6. This substance has good absorption into and high retention in wood.