A method for preparing nanohydrogels comprising a dispersion step, in which a polysaccharide functionalized with hydrophobic molecules and in the form of a macromolecular agglomerate is dispersed in an aqueous solution, and a heating step, in which the aqueous dispersion of the polysaccharide is subjected to a temperature of between 70° C. and 150° C. and a pressure of between 1 bar and 5 bar. In the heating step, the conditions of temperature and pressure must be such that boiling of the aqueous dispersion of the polysaccharide does not take place.
