Agent (I) comprises at least an oxidative dye precursor and an active combination of at least a basic amino acid and pyrrolidone carboxylic acid or its salt, in a carrier, where (I) is preferably free of acidic amino acid. Independent claims are included for: (1) dyeing keratin fibers, preferably human hair comprising mixing an agent (A) containing at least one dye with an agent (B) containing at least one oxidizing agent, before the application, applying the obtained mixture on the fibers and rinsing after a contact time of 1-60 minutes, where the agent (A) and/or the resulting application preparation contains the active combination and (2) kit for coloring keratin fibers comprising at least a first packing unit containing the agent (A) and a second packing unit containing the agent (B).
