A composition and method for using the composition for dyeing keratin fibers. The composition consists of indole/indoline hybrid dyes and hybrid dye precursors. More particularly, the indole/indoline hybrid dyes and hybrid dye precursors correspond to formula (I): X—S—Y  (I) where X is a group derived from an indole or indoline derivative as a melanin precursor, Y is a group derived from an oxidation dye precursor of the secondary or primary intermediate type or an indole or indoline derivative as a melanin precursor; and S is a structural element which is common constituent of the groups X and Y, a direct bond or at least one spacer group. The composition may also be used to color human skin.