Multicenter clinical trial or TMS-19-Q.O tablet was performed to evaluate the usefulness in oral surgery. The results obtained were as follows: Clinical efficacy was assessed by clinical points. The patients entered into the trial were 77 cases with periodontitis, 23 with pericoronitis, 92 with osteitis of jaw and 18 with other infections, and the each effective rates were 80.5, 60.9, 83.7 and 72.2%, respectively. Overall effective rate was 79.0%. Isolation frequency of organisms were 33.8% in periodontitis, 34.8% in osteitis of jaw and 17.4% in pericoronitis. Bacteria isolated were aerobic organisms (63.1%) and anaerobic organisms (36.9%). TMS-19-Q.O tablet was well tolerated, and no adverse reaction was observed.