Aim: The aim of this study was to examine the effects of pentadecapeptide BPC 157 independently and in combination with conventional antibiotics in vitro microdilution and disc-diffusion sensitivity testing. Materials and Methods: For testing antibacterial effects of BPC 157 and its interaction with antibiotics, standard as well as clinical isolates of the most significant bacterial infection pathogens have been selected. The study included a total of 120 susceptible and resistant bacterial strains isolated from clinical specimens: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa; as well as ATCC strains: Staphylococcus aureus 25923, Enterococcus faecalis 29212, Pseudomonas aeruginosa 27853, Escherichia coli 25922, Acinetobacter baumannii 19606, Klebsiella pneumoniae 700803. For testing of synergistic or antagonistic effect the antibiotics for Gram positive strains were used such as ampicillin, erythromycin, gentamicin, vancomycin, while amikacin, ceftazidime, ciprofloxacin and imipenem were used for Gram negative strains. Results: The synergistic or antagonistic effects between the BPC 157 and the selected tested antibiotics by the disc diffusion method are not detected for any tested concentration and for investigated bacterial strains by the dilution test within the exception of the combination of imipenem and BPC 157 in susceptible strains of E. coli. Conclusion: BPC 157 could be safely used with the antibiotic used in the present study and it cannot interfere with the antibiotic effects. Since no particular antibiotic activity was detected, unlike regular antimicrobial peptides, the beneficial effects previously described would certainly be unrelated to any kind of bacterial resistance.