Protein may be removed from fluids by adsorption onto inorganic oxide-silica cogels. Preferred cogels are silica alumina and silica magnesia activated so that the cogel surface is in acid form, with H.sub.0 values less than the pH of the protein-containing fluid which, in turn, is less than the isoelectric point of the protein. The method is particularly effective for removing haze-forming proteins from wine.