The invention relates to a synergic pharmaceutical composition of mebendazole (MBDZ) with nitazoxanide (NTZX) for the treatment of human parasitosis, which significantly increases the spectrum of MBDZ against protozoa and reinforces the anthelmintic action of NTZX. Furthermore, when said pharmaceutical combination of MBDZ and NTZX is used, the same effects of the individual active substances are maintained in the systemic action of the active metabolite of NTZX, tizoxanide, and in the treatment of some systemic forms of parasitosis. In addition, the synergic pharmaceutical combination of MBDZ with NTZX achieves a larger anti-parasite spectrum, while maintaining the efficiency and safety profiles of both active substances independently. All of these effects enable the differentiation of the pharmaceutical combination from the rest of the conventional anti-parasite treatments that have more limited spectra. The invention therefore relates principally to the synergic effects of the pharmaceutical combination of MBDZ and NTZX.