The invention relates to the use of an additive to stabilise hyaluronic acid formulated in an aqueous composition against the degrading effect of heat or of enzymes such as hyaluronidase, characterised in that said additive comprises one or more polysaccharides having a molecular weight equal to or greater than 20,000 daltons and solubility in water at least equal to or greater than 1 g/l, the total concentration of said polysaccharide(s) and hyaluronic acid in the composition giving it a viscosity of at least 500 cP, which is particularly suitable for intra-articular, intradermal or intraocular administration to humans or animals.
