The present invention relates to novel dyeing assistant preparations comprising, as component (a), at least one amine oxide of the formula ##STR1## in which R is an aliphatic radical having 8 to 24 carbon atoms andR.sub.1 is an aliphatic radical which is unsubstituted or substituted by hydroxyl and has 1 to 24 carbon atoms, preferably 1 to 6 carbon atoms,as component (b), at least one compound of the formulaR.sub.2 --U--(R.sub.3 --O).sub.m --W (2),in whichR.sub.2 is an aliphatic radical having 8 to 24 carbon atoms,R.sub.3 is alkylene having 2 to 4 carbon atoms,U is --O-- or ##STR2## in which Z is a direct bond, (R.sub.3 --O)).sub.r or C.sub.1 -C.sub.6 alkylene andW.sub.1 is hydrogen or C.sub.1 -C.sub.6 alkyl which is unsubstituted or substituted by hydroxyl, carboxyl, isocyanato, phenyl, benzyloxymethylene or phenethyloxymethylene, m and r independently of one another are a number from 2 to 25,(R.sub.3 --O).sub.m is m identical or different radicals (R.sub.3 --O) and(R.sub.3 --O).sub.r is r identical or different radicals (R.sub.3 --O), andW is hydrogen or C.sub.1 -C.sub.6 alkyl which is unsubstituted or substituted by hydroxyl, carboxyl, isocyanato, phenyl, benzyloxymethylene or phenethyloxymethylene, and, as component (c), an organic solvent, and to their use as dyeing assistants for dyeing wool.