Tamoxifen is a selective estrogen receptor modulator, mainly used for the treatment of recurrent metastatic breast cancer in women, adjuvant therapy after surgical metastasis of breast cancer and the prevention of recurrence after surgery. Tamoxifen has certain adverse reactions such as nausea, vomiting, diarrhea; occasional leukopenia, liver function abnormalities; menstrual disorders, amenorrhea, irregular vaginal bleeding, etc.; retinopathy or corneal clouding; as well as pulmonary embolism, thrombosis and so on. It is recommended that the medication be taken under the supervision of a physician.