1,5-diphenylpyrazole-3-carboxylic acid derivatives of the formula ##STR1## in which each of R.sub.a and R.sub.b, independently of the other represents halogen, C.sub.1 -C.sub.5 -alkyl, C.sub.1 -C.sub.5 -haloalkyl, C.sub.2 -C.sub.5 -alkenyl, C.sub.2 -C.sub.5 -alkynyl or cyano, n represents zero or an integer from 1 to 3, and OR.sub.1 represents hydroxy, a plant-physiologically tolerable salt radical or any desired ester radical, are capable of antagonizing specifically the phytotoxic action of phenoxypropionic acid ester herbicides of the formula II ##STR2## in which G represents ##STR3## in which Hal.sub.1 represents fluorine, chlorine, bromine, iodine or trifluoromethyl, Hal.sub.2 represents hydrogen, fluorine, chlorine, bromine or trifluoromethyl, Z represents nitrogen or methine (--CH.dbd.), X represents an oxygen or sulphur atom, R.sub.1 ' represents halogen, trifluoromethyl, nitro, cyano, C.sub.1 -C.sub.4 -alkyl or C.sub.1 -C.sub.4 -alkoxy and n represents 0, 1, 2 or 3 and T represents an ester, amide, cyanamide or oxime radical.Compositions, containing those components, as selective herbicides and the use of those two active ingredients for controlling weeds in crops of useful plants are described, as are also novel 1,5-diphenylpyrazole-3-carboxylic acid derivatives corresponding to the formula I and the preparation thereof.