Histologic reactions of bone and soft tissue to CFRE were explored, and biomechanical properties of both CFRE plate and stainless steel plate were tested and compared. Six achilles tendons of albino rabbits were replaced with CFRE implant after artificial rupture and serial histologic examination of neotendon and histologic response in vivo were done during 8 weeks. Proximal tibia of twelve albino rabbit was selected, subjected the tibia a single osteotomy and internal fixation with CFRE plate in six cases, and stainless steel plate in the others. And then, consequent radiographic and histologic change was observed during 8 weeks. Objectives in this paper is to provide basic data of CFRE in its biomechanical and biologic response in vivo. The results were as follows :1. Foreign body reaction and fibroblast were decreased at 7-8 weeks after operation. Early formation of collagen, which is similar to that found in the normal side, was shown. So, CFRE seems to be ideal material in the aspect of tissue tolerance among biocomaptibility factors. 2. In biomechanical test, CFRE plate is lower than stainless steel plate in flexural strength and flexural modulus. This means that CFRE plate is semirigid in nature. 3. While external callus formation is marked after fixation of CFRE, internal callus for mation is marked after fixation of stainless steel plate. In CFRE plated tibia, the resorption-cavity is much smaller than stainless steel plated, and there is some formation of woven bone beneath the plate. In conclusion, CFRE is ideal material in the aspect of its biomechanical compatibility and tissue tolerance. Further efforts on production and varying design of CFRE make it to use widely in clinical application, Such as internal fixator of fracture and temporary replacement of tendon or ligament.