Letrozole tablets have many side effects, most of which are treated symptomatically. For example, in case of joint pain, non-steroidal anti-inflammatory drugs such as ibuprofen extended-release capsules can be used for relief; in case of hypercholesterolemia, simvastatin capsules can be used for control; in case of gastrointestinal reactions such as nausea and vomiting, metoclopramide hydrochloride injection can be given intramuscularly or intravenously. Letrozole is used in the treatment of estrogen or progesterone receptor-positive breast cancer patients and is a chemotherapeutic drug whose side effects can involve multiple systems. The most common side effects include hot flashes, arthralgia, hypercholesterolemia, nausea, and fatigue; less common are neurologic effects such as dizziness and headache, cardiovascular effects such as tachycardia and hypertension, and respiratory effects such as dyspnea. Letrozole acts through estrogen and progesterone pathways, therefore, for patients whose menopausal status is unclear, luteinizing hormone, follicle stimulating hormone and/or estrogen levels should be tested before using the drug, and subsequent treatment should be carried out only after postmenopausal endocrine status has been confirmed. Please note that the drug is contraindicated in patients who are allergic to it; in pregnant and lactating women; in children and adolescents. If you need to use the drug, please be sure to take the drug under the guidance of a doctor and strictly comply with the doctor’s instructions, do not self-medication.