Crop-protecting compositions containing isoxazolines or isothiazolines, novel isoxazolines and isothiazolines, and their preparationCrop-protecting compositions which contain isoxazolines or isothiazolines of the formula ##STR1## in which X is oxygen or sulfur, R is hydroxyl or has the meanings given in the description, Z is halogen, nitro, cyano, in each case optionally substituted alkyl, alkoxy, alkylmercapto, cycloalkyl, amino, hydroxymethyl, alkylamino, dialkylamino, alkoxymethyl, aryl or aryloxy and n is an integer from 0 to 5. Novel isoxazolines and isothiazolines of this formula, a process for their preparation, and their use as a protection against phytotoxic secondary effects of herbicides.