The invention relates to a method for dyeing keratin fibers, especially human hair. The inventive method comprises the following steps: optionally applying a pretreatment agent M1 to the fiber, using a dye M2 on the fiber which is optionally mixed immediately before application to the fiber from a component M2a, containing at least one oxidative dye pre-product of the developer type and/or an indole and/or indole derivative and a component M2b, containing an oxidative dye and/or an enzyme. If desired, a third agent M3 is added to the individual agents M2a or M2b before mixing them or to the mixture M2, and said dye M2 is rinsed from the fiber after a period of 5–10 minutes. At least one of the agents M1, M2a, M2b or M3 contains a compound from the vitamin B6 group. The invention further relates to hair pretreatment agents, to agents for dyeing keratin fibers, to their packing in corresponding kits and to the use thereof. The inventive compounds of the vitamin B6 group and their physiologically acceptable salts are useful as coupling components in the production of oxidative dyes that contain conventional developer and/or coupling compounds and/or indole and/or indole derivatives in a substrate appropriate for dyeing. The inventive compounds are further useful as active substances that improve the hair structure.