Chronic osteomyelitis is a difficult orthopaedic problem to be treated especcially if the causative organism is gram negative, such like Pseudomonas aeruginosa. Clinical trial of ceftazidime to treat chronic osteomyelitis due to P. aeruginosa had been performed in 22 patients from January 1993 to April 1993. All patients were with history to open fracture grade IIIA and IIIB (Gustilo-Anderson) …