SERMs (selective estrogen receptor modulators) are a new type of medicine. Raloxifene (approved by the Food and Drug Administration to prevent osteoporosis) and tamoxifen (approved for breast cancer treatment and prevention) are examples of SERMs. They are designed to do some of the good things estrogen does such as protecting bone density. However, they may not have some of the negative side effects. For example, tamoxifen appears to protect against developing breast cancer. Raloxifene does not seem to increase the chance of endometrial cancer as estrogen alone or tamoxifen might. Women on tamoxifen should see their gynecologist regularly to be sure their uterus is normal. These two SERMS do, however, have a risk of blood clots similar to estrogen. Also, raloxifene and tamoxifen can make hot flashes worse. Scientists are continuing to work on developing better SERMs to use for menopause in the future.