A synergistic herbicidal mixture comprising A) at least one 3-heterocyclyl-substituted benzoyl derivative of the formula I in which the variables have the following meanings: R1, R3 are hydrogen, halogen, alkyl, halogenalkyl, alkoxy, halogenalkoxy, alkylthio, alkylsulfinyl or alkylsulfonyl; R2 is a heterocyclic radical selected from the group: thiazol-2-yl, thiazol-4-yl, thiazol-5-yl, isoxazol-3-yl, isoxazol-4-yl, isoxazol-5-yl, 4,5-dihydroisoxazol-3-yl, 4,5-dihydroisoxazol-4-yl and 4,5-dihydroisoxazol-5-yl, it being possible for these to be unsubstituted or mono- or polysubstituted by halogen, alkyl, alkoxy, haloalkyl, haloalkoxy or alkylthio; R4 is hydrogen, halogen or alkyl; R5 is alkyl; R6 is hydrogen or alkyl; or one of its environmentally compatible salts; and B) a synergistically effective amount of at least one herbicidal compound from the group of the acetyl-CoA carboxylase inhibitors (ACC), acetolactate synthase inhibitors (ALS), amides, auxin herbicides, auxin transport inhibitors, carotenoid biosynthesis inhibitors, enolpyruvylshikimate-3-phosphate synthase inhibitors (ESPS), glutamine synthetase inhibitors, lipid biosynthesis inhibitors, mitosis inhibitors, protophorphyrinogen [sic ] IX oxidase inhibitors, photosynthesis inhibitors, synergists, growth substances, cell wall biosynthesis inhibitors and a variety of other herbicides. Compositions comprising these mixtures, processes for the preparation of these compositions, and their use for controlling undesired plants.