The use of indolines of formula (I):
##STR1##
in which R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 independently of
one another represent hydrogen or C.sub.1-4 alkyl groups, or R.sup.4 and
R.sup.5 together with the oxygen atoms to which they are attached may
represent an alkylenedioxy group containing 1 to 4 carbon atoms, or their
salts, as oxidation dye precursors gives natural brown hair colorings. The
indolines of formula (I) are also suitable as couplers in oxidation hair
dyes with a conventional primary intermediate, in which they result in a
modification of the tints obtainable with the primary intermediate. They
are used in conventional carriers, e.g., in gel or emulsion form,
preferably mixed before use or on the hair with an oxidizing agent to
develop the color.
