In vitro and in vivo antibacterial activities of TOC-50, a new parenteral cephalosporin, were assessed against Enterococcus faecalis. In vitro, TOC-50 had excellent activity, stronger than that of penicillin G, sulbactam/ampicillin, tazobactam/piperacillin, the cephalosporins tested, imipenem, vancomycin, gentamicin, tobramycin, arbekacin, amikacin, minocycline and ofloxacin against clinically isolated strains. In addition, TOC-50 was more active than penicillin G, sulbactam/ampicillin and imipenem against vancomycin-resistant E. faecalis NCTC 12201. In terms of bactericidal effect against the same strain, TOC-50 was superior to sulbactam/ampicillin and imipenem. In murine systemic infection models, TOC-50 had a potent protective activity against E. faecalis 42. Its protective activity was stronger than that of imipenem or vancomycin.