Demineralized human bone used as an autologous bone graft substitute is ethylene oxide sterilized, which is reported to reduce the bone's osteoinductive potential. To determine the minimum sterilization time required and the effect of ethylene oxide on bone's osteoinductive capacity and chemical structure, samples were exposed to ethylene oxide for different times (5-240 min). Results showed that 1 h exposure sterilized the bone (assessed by Attests). This exposure time reduced the bone's osteoinductive potential and caused surface ultrastructural changes. These findings raise questions concerning the suitability of ethylene oxide for sterilizing demineralized human bone.