This study was undertaken to investigate the effects of the Ginseng radix in osteoporosis of the oophorectomized rats. In this experiment, the rats were oophorectomized and administered the water extracts of the Ginseng radix. The spinal bone mineral density, calcium, phosphorus and ash weight of the bones were measured. The spinal bone mineral density was significantly increased in the ovariectomized (OVX)-Ginseng radix group at 8 weeks as compared to the OVX-saline group. Furthermore, the calcium and phosphorus contents of the femoral and fibula-tibia were significantly increased in the OVX-Ginseng radix group as compared to the OVX-saline group. The ash weights of the femoral and fibula-tibial bones were increases in the OVX-Ginseng Radix group, although it was not statistically significant. On reviewing these experiments, it appears that the Ginseng radix possess efficacy for the prevention of osteoporosis. Further study would be of value to confirm the efficacy of the Ginseng radix for the treatment and/or prevention of osteoporosis in humans.