Use of an aqueous solution of a cationic copolymer in a detergent composition, characterized in that the cationic copolymer is formed from a cationic monomer and a nonionic monomer wherein said cationic copolymer has an average molecular weight in the range 30,000 to 300,000 and the aqueous solution has a concentration of 20 to 50% by weight and a viscosity of less than 10,000 cP at 25.degree. C. The invention also claims cosmetic compositions obtained from the aqueous solution of a cationic copolymer.