The present invention relates to the field of medicine, specifically, to the field of chemical and pharmaceutical industry and concerns ezrin-derived peptides, in particular, a peptide comprising an amino acid sequence of general formula (I) X1 EKKRRETVERE X2X3, wherein each X represents a non-polar amino acid residue. The use of the peptides as immunostimulatory agents, and more specifically, for use in treating and preventing antiviral, antibacterial and antifungal infections, and treatment of diseases of the GI tract, in particular ulcerative disorders of the GI tract. The present invention also relates to pharmaceutical compositions comprising the peptides. Further, the invention relates to methods of treatment of infection and ulcerative diseases of the GI tract comprising administering the peptides to patients in need thereof.