A process for protecting cultivated plants against aggressive agricultural chemicals is described in which oxime derivatives of the formula ##STR1## are used as antidotes. Either the cultivated area for the cultivated plants or the cultivated plants themselves or parts of the plant (seeds, tubers, stem parts and the like), as desired, can be treated with these oxime derivatives, which are used as a dressing.Ar is a phenyl radical of the formula ##STR2## or Ar is also a 5-membered to 10-membered heterocyclic radical which contains not more than three identical or different hetero-atoms N, O and/or S and which can be bonded via a C.sub.1 - to C.sub.3 -aliphatic chain to the remainder of the molecule and which is substituted by R.sub.1, R.sub.2 or R.sub.3 and can be substituted by oxo or thiono; X is hydrogen, CN, halogen, C.sub.1 -C.sub.10 -alkyl, lower alkanoyl, --COOH, a carboxylic acid ester of a carboxamide radical; and Q is hydrogen, lower alkyl, which can be interrupted by hetero-atoms or substituted by halogen or cyano, lower alkenyl or halogenoalkenyl, lower alkynyl, C.sub.3 -C.sub.7 cycloalkyl, which is unsubstituted or substituted by halogen, or a lower alkanecarboxylic acid ester group, a lower alkanecarboxylic acid thioester group, a lower alkanecarboxamide group, an aliphatic acyl radical, an araliphatic, cycloaliphatic or substituted or unsubstituted aromatic or heterocyclic acyl radical, an alkylsulfonyl radical, a sulfonamide radical, a metal salt, a quaternized ammonium salt or an aliphatic, araliphatic, cycloaliphatic or substituted or unsubstituted aromatic or heterocyclic carbonic acid, thiocarbonic acid or carbamoyl radical.