The in vitro activities of tigecycline were tested against 831 isolates of the Bacteroides fragilis group representing all of the species within the group. On a weight-to-weight basis (8 microg/ml), tigecycline was more active than clindamycin, minocycline, trovafloxacin, and cefoxitin and less active than imipenem or piperacillin-tazobactam against all isolates of the B. fragilis group. Tigecycline geometric mean MICs were statistically higher against B. distasonis than other Bacteroides species (P value of 0.0001).