Compounds of the formula (I) or salts thereof, which R1 is COOH or a derivative thereof, preferably a radical of the formula —CN, —C(═X)—Y—R or —C(X′R′)(X″R″)—Y—R, in which R is H, a (subst.) hydrocarbon radical, a heterocyclic radical or acyl, Y is a direct bond or O, S, NRc or NRc—NRdRe, n is the integer 1, 2, 3, 4, 5 or 6 and R′, R″, X, X′, X″, Ra, Rb, Rc, Rd, Re, R2, R3 (R4)m are as defined in claim 1 are suitable as safeners for crop plants or useful plants against phytotoxic actions of agrochemicals, preferably as safeners against the action of pesticides such as herbicides in these plants, where compounds of the formula (I) or salts thereof in which R1 is COOH, R2, R3 are each hydrogen, (R4)m is a hydroxyl radical (m=1) in any position or two radicals R4 (m=2) in any position, where in the latter case one radical is a hydroxyl group and the other radical is hydroxyl or methoxy, and n is the number 1, are used as safeners for crop plants or useful plants against phytotoxic actions of agrochemicals other than glyphosate.