An agent for coloring keratin fibers, in particular human hair, characterized in that it contains, in a cosmetic carrier, (a) at least one compound of formula in which R1, R2, R3 each represent, independently of one another, hydrogen, halogen, a nitro group, a cyano group, a carboxyl group, a sulfonic acid group, a hydroxy group, a C 1 -C 6 acyl amino group, a carboxamide group, a sulfonamide group, a C 1 -C 6 alkyl group, C 1 -C 6 alkoxy group, a C 2 -C 6 alkenyl group, a C 2 -C 6 hydroxyalkyl group or a C 1 -C 6 alkoxy-C 2 -C 6 alkyl group; R4, R5, R6 each represent, independently of one another, a C 1 -C 6 alkyl group, a C 2 -C 6 alkenyl group, a C 2 -C 6 hydroxyalkyl group or a C 1 -C 6 alkoxy-C 2 -C 6 alkyl group; X, Y, Z each represent, independently of one another, hydrogen or an N group, in which R7 and R8 each represent, independently of one another, hydrogen, a C 1 -C 6 alkyl group, a C 2 -C 6 alkenyl group, a C 2 -C 6 hydroxyalkyl group or a C 1 -C 6 alkoxy-C 2 -C 6 alkyl group, with the proviso that at least one of the functional groups X, Y and Z represents an N group, n represents a number from 2 to 6, A - represents a physiologically acceptable anion, and (b) at least one alkylamphodiacetate and/or alkylamphodipropionate as an amphoteric surfactant. (a) at least one compound of formula in which R1, R2, R3 each represent, independently of one another, hydrogen, halogen, a nitro group, a cyano group, a carboxyl group, a sulfonic acid group, a hydroxy group, a C 1 -C 6 acyl amino group, a carboxamide group, a sulfonamide group, a C 1 -C 6 alkyl group, C 1 -C 6 alkoxy group, a C 2 -C 6 alkenyl group, a C 2 -C 6 hydroxyalkyl group or a C 1 -C 6 alkoxy-C 2 -C 6 alkyl group; R4, R5, R6 each represent, independently of one another, a C 1 -C 6 alkyl group, a C 2 -C 6 alkenyl group, a C 2 -C 6 hydroxyalkyl group or a C 1 -C 6 alkoxy-C 2 -C 6 alkyl group; X, Y, Z each represent, independently of one another, hydrogen or an N group, in which R7 and R8 each represent, independently of one another, hydrogen, a C 1 -C 6 alkyl group, a C 2 -C 6 alkenyl group, a C 2 -C 6 hydroxyalkyl group or a C 1 -C 6 alkoxy-C 2 -C 6 alkyl group, with the proviso that at least one of the functional groups X, Y and Z represents an N group, n represents a number from 2 to 6, A - represents a physiologically acceptable anion, and R1, R2, R3 each represent, independently of one another, hydrogen, halogen, a nitro group, a cyano group, a carboxyl group, a sulfonic acid group, a hydroxy group, a C 1 -C 6 acyl amino group, a carboxamide group, a sulfonamide group, a C 1 -C 6 alkyl group, C 1 -C 6 alkoxy group, a C 2 -C 6 alkenyl group, a C 2 -C 6 hydroxyalkyl group or a C 1 -C 6 alkoxy-C 2 -C 6 alkyl group; R4, R5, R6 each represent, independently of one another, a C 1 -C 6 alkyl group, a C 2 -C 6 alkenyl group, a C 2 -C 6 hydroxyalkyl group or a C 1 -C 6 alkoxy-C 2 -C 6 alkyl group; X, Y, Z each represent, independently of one another, hydrogen or an N group, in which R7 and R8 each represent, independently of one another, hydrogen, a C 1 -C 6 alkyl group, a C 2 -C 6 alkenyl group, a C 2 -C 6 hydroxyalkyl group or a C 1 -C 6 alkoxy-C 2 -C 6 alkyl group, with the proviso that at least one of the functional groups X, Y and Z represents an N group, n represents a number from 2 to 6, A - represents a physiologically acceptable anion, and (b) at least one alkylamphodiacetate and/or alkylamphodipropionate as an amphoteric surfactant.