The present invention relates to microcapsules with a double-layer of natural polysaccharides - chitosan and alginate - gelified and stabilized by means of a divalent ion containing inside at least one biologically active substance. The microcapsules of the invention can be employed as carriers for the oral administration of biologically active substances, also associated with an adjuvant of the biological response of the same, administered for a preventive or therapeutic purpose. These substances can be chosen, for example, from antigens and adjuvants, suitable for immune response stimulation against infective and non-infective agents, or from chemotherapeutics and adjuvants with therapeutic type effects. According to the type of biologically active substance encapsulated in the microcapsules, there can be a variety of uses for oral vaccination or therapy in the human and veterinary field.
