Evista is for the treatment and prevention of osteoporosis. Patients that are pregnant, or may still become pregnant, should not take this medication. It is for the patients that have already gone through menopause. Although the medication may reduce the risk of breast cancer, it increases the chances of developing blood clots or having a stroke. So, if you experience swelling in your legs, discomfort in your chest, or other negative symptoms, contact your doctor immediately. You do not want to stroke out or have a blood clot that travels to your lungs. Of course, if you have trouble breathing, it can also be a symptom of a lung clot. But, do not decide to quit taking the medication. You doctor will have to wean you off of Evista.