Interaction of the dispersed phase of the fullerene C-60 hydrosol with ca tionic dyes, Indopolycarbocyanines, Methylene Blue and others, results in the adsorption of the dyes on the surface of colloidal particles. The phenomenon is accompanied by expressed changes in the absorption spectra of all the dyes, as well as in fluorescence quenching in the case of Indotricarbocyanine, and leads to the coagulation of the sol. The structural forces, caused by hydrophobization of the fullerene-water interface, play a decisive role in the coagulation phenomena.