Nontuberculous mycobacteria (NTM) have recently emerged as important bacterial pathogens of both animals and humans. In this study, we aimed to evaluate the effect of a combination of ten antibiotics with an inhibitor of efflux pumps (EPI), i.e. berberine (BER), against 6 strains of NTM. Our results showed that the BER potentiated the anti-mycobacterial activities of the antibiotics. Overall, our findings show the importance of BER in increasing the efficacy of antibiotics in NTM