Selective estrogen receptor modulators (SERMs) bind to estrogen receptor (ER) 
and develop tissue-selective actions as estrogen agonists or antagonists. As 
such, SERMs have been developed to exert estrogen-like beneficial effects 
against some disorders including osteoporosis, while reducing estrogen-related 
risks, including breast cancer. Prevention of vertebral fractures by a SERM, 
raloxifene (RLX), in osteoporotic postmenopausal women has been well 
established. RLX does not increase or decrease cardiovascular events, overall 
mortality, cardiovascular mortality or the overall number of strokes, but there 
appears to be a small increase in stroke mortality. Both RLX and tamoxifen 
similarly reduce the risk of ER-positive invasive breast cancer. At the same 
time, RLX treatment is associated with 36% fewer uterine cancer incidence and 
29% less thromboembolic events. Keeping these results in mind, it is our 
responsibility to critically evaluate and decide timing and length of treatment, 
as well as subjects with benefits or risks for the treatment of osteoporosis by 
SERMs.