Purpose: This study was carried out to investigate the effects of Guibi Tang(GT) and Placenta Hominis blended Guibi Tang(GTPH) on the postmenopausal osteoporosis. Methods: In order to observe the potential effects of GT and GTPH on the osteoporosis induced by ovariectomy, antioxidative effects of GT and GTPH were measured. Antioxidative activity for the samples was investigated by Rancimat method. Animals were observed for 8 weeks, and vehicle and extracts of prescriptions were administered ad libitum. And we measured the variance of body weight, femoral bone weight, serum level of osteocalcin, calcium, alkaline phosphatase(ALP), estradiol, cholesterol, triglyceride, alanine aminotransferase(ALT) and creatinine. Results: As a result, GTPH showed antioxidative effect, but did not in GT. Body weight increased significantly in 6 weeks after ovariectomy, and the weight of GTPH administered group decreased significantly. GT and GTPH decreased the serum level of cholesterol and triglyceride. Administration of GTPH increased the serum level of ALP when compared with control group. Ovariectomy and GT, GTPH administration had no influence on serum level of ALT and creatinine. Conclusion: According to above results. We suggest that GT and GTPH may be used prevention and curing the postmenopausal osteoporosis.