Tamoxifen commonly used in hormone therapy to treat breast cancer. It can slow or stop cancer cell growth and prevent new cancer in the other breast.

However, it does have some side effects. Menopausal symptoms including vaginal dryness, hot flashes, low libido, nausea, and mood swings are the most common symptoms.

Other rare side effects are more dangerous. These are:

• Overgrowth of uterus lining (endometrial hyperplasia) and cancer of uterus lining (endometrial cancer).
• Increased risk of blood clots in the lungs (pulmonary embolism) and the legs (deep vein thrombosis).
• Increased risk of cataract.
• Increased risk of stroke.
• Ovarian cysts