Concentrations of cefotiam (CTM) in the exudate after abdominal operation were studied. The exudates were collected by 6 mm paper discs and the antibiotic concentrations were determined by the paper disc method using Proteus rettgeri ATCC 9250 as test organism. Comparison between agar well and paper disc assay for CTM in ascites specimens showed good correlation. Two grams of CTM was intravenously given to the patients after abdominal operations. The concentration of CTM in the exudate for 6 hours after injection was 0.4-14.2μg/ml and this value exceeded the antibacterial level of CTM.It is, therefore, concluded that CTM will be effective for the postoperative prophylaxis.
