Letrozole is a medication used to treat certain types of breast cancer in postmenopausal women. It works by blocking the production of estrogen, a hormone that can promote the growth of breast cancer cells.  

Common uses of letrozole include:

• Treatment of breast cancer: As a first-line treatment for postmenopausal women with hormone-receptor-positive breast cancer.
• Adjuvant therapy: To reduce the risk of breast cancer recurrence after surgery and chemotherapy.

Note: Letrozole can have side effects, such as hot flashes, joint pain, and vaginal dryness. It’s important to consult with a healthcare professional before taking letrozole or any other medication.