Safety and Efficacy Study of Bugusan (BGS)to Treat Osteoporosis.

Inclusion Criteria: 1. Postmenopausal women between the ages of 45 and 75 years with a natural menopause ≧ 6 months and serum E2 values \< 20 pg/ml, serum FSH values ≧ 25 mIU/mL; 2. Patients have bone mineral density \<-2.5 SD of T score at the lumbar spine (L2-L4); 3. All patients must sign the informed consent form (ICF) prior to the trial. Exclusion Criteria: 1. Any X-ray film that documents substantial scoliosis, or spinal secondary osteoporosis; 2. Any X-ray film that documents bone fracture within 3 month prior to the trial. 3. Medication such as estrogen, bisphosphonates, calcitonin, fluoride, glucocorticoids, ipriflavone intake within 3 weeks prior to the trial; 4. Use of other Chinese medicine within 2 weeks prior to the trial; 5. Patients with significant renal function impairment (Creatinine\>2mg/dl) and liver function impairment (AST and ALT \> 2 x the upper limit of normal range); 6. Patients have laboratory test abnormality, which in the investigator's opinion might confound the study; 7. Patients have severe cardiac disease, e.g. unstable angina pectoris, myocardial infarction, congestive heart failure (New York Heart Association Functional Classification III and IV); 8. Patients have life threatening disease; 9. Patients are allergic to any of the composition of Chinese medicine; 10. Significant concomitant disease or medical history that could interfere with the study as judged by the investigator;