Compositions comprising at least one water-insoluble ingredient and at least one copolymer of

A) from 5 to 99% by weight of at least one N-vinylcarboxamide of the formula I ##STR1##

where R¹ and R² independently of one another are hydrogen or C₁-C₆-alkyl;

B) from 1 to 95% by weight of at least one monomer having a hydrophobic radical which can be copolymerized with vinylcarboxamides of the formula I; and optionally

C) from 0 to 94% by weight of at least one other copolymerizable monomer,

and the use of the above copolymers as solubility promoters.