The present invention relates to a composition for use as support therapy in antitumor chemotherapeutic treatments, in acquired immunodeficiency syndrome treatments and in leukemia treatments. Said composition comprising a bacterial strain belonging to the species Lactobacillus pentosus and having an antiviral and an antibacterial activity, and a highly bioavailable zinc internalized in a tyndalized bacterial cell mixed with at least one rubber, preferably an alginate and/or a gel, preferably a gel.