The invention relates to the use of a water-soluble or water-dispersible
linear block copolymer comprising at least one hydrophulic block and at
least one hydrophobic block, the hydrophilic block representing at least
30% by weight of the linear block copolymer, with the exclusion of block
copolymers of ethylene oxide and propylene oxide, block copolymers
containing urethane units and block copolymers containing siloxane units,
to thicken or gel aqueous hair treatment compositions containing at least
one polymer that is beneficial for the hair, and also to aqueous hair
compositions thickened or gelled with such a block copolymer.