Ranicefulcorner[Cefpimizole sodium] is a new semisynthetic cephalosporin C derivative, was administered to 30 patients with empyema thoracis to evaluate its efficacy from Nov. 1989 to May 1990 at Department of Thoracic & Cardiovascular Surgery, Dongsan Medical Center, Keimyung University. The results were as follows. 1. The clinical efficacy of therapy was excellent in 15 cases, effective in 11 cases and failure in 4 cases. The effectiveness rate was 86.7%, respectively. 2. Among 30 cases organisms were cultured in 19 cases and 24 clinical strains were isolated. ulcorner-hemolytic streptococcus[5], S. epidermidis[4], Pseudomonas aeruginosa[3], E. coli[3 of 5 cases], S. aureus[3 of 4 cases] and Klebsiella pneumoniae[1 of 2 cases] were effective to Ranicefulcorner 3. Abnormal clinical values, a decrease in platelet was observed in 3 cases and slight increases of s-GOT/GPT in 2 cases. But they were not so severe that they improved without. There were two cases of mild gastrointestinal symptom.