Ten patients received 2000 mg of ceftazidime intravenously before undergoing lower-extremity amputation for ischaemia. Bone and plasma concentrations were determined by HPLC. The bone concentrations were corrected for blood contamination. In all but one sample ceftazidime was detectable. The median concentration in the midfoot, 4.8 microg/g (range 1.2-11.4 microg/g), was higher than the median concentration in the forefoot, 3.1 microg/g (range 0.8-15.7 microg/g) (P <0.05). In the majority (>90%) of bone samples taken from sites with gangrenous skin the ceftazidime concentration was >1.8 mg/kg bone. The present data indicate that ceftazidime penetrates into bone of severely ischaemic limbs.