5-Amino-4-heterocyclyl-1-phenylpyrazoles of the formula ##STR1## in which R.sup.1 represents hydrogen or alkyl,R.sup.2 represents hydrogen or a radical ##STR2## R.sup.3 represents hydrogen, ##STR3## alkyl, alkenyl or alkinyl, R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 independently of one another represent hydrogen, cyano, nitro, halogen, alkyl, alkoxy, alkoxycarbonyl, halogenoalkyl, halogenoalkoxy or a radical --S(O).sub.n --R.sup.10,R.sup.9 represents hydrogen, alkyl, alkenyl, alkinyl, halogenoalkyl, alkoxyalkyl, alkylthioalkyl, optionally substituted cycloalkyl, optionally substituted aryl, alkoxy, alkylthio, optionally substituted aryloxy or aryloxyalkyl, optionally substituted arylthio, alkylamino, dialkylamino or optionally substituted arylamino,R.sup.10 represents alkyl, halogenoalkyl, amino, alkylamino or dialkylamino,X represents oxygen or sulphur,n represents the number 0, 1 or 2 andHet represents a saturated or unsaturated optionally substituted heterocyclic radical,exhibit herbicidal and plant growth-regulating activity.