The duration of methotrexate depends on the specific condition, and it is usually taken for a period of 1 to 2 years, and it is not recommended to take it for a long period of time. Methotrexate is a folate reductase inhibitor, which can inhibit DNA biosynthesis, and is commonly used clinically in the treatment of various types of acute leukemia, head and neck cancer, lung cancer, psoriasis, breast cancer, ovarian cancer and other diseases. Methotrexate is generally not prescribed to be taken for a maximum of a few years, and is generally taken for a period of 1 to 2 years, but should be judged accordingly to the patient’s condition, and long-term use is not recommended. Adverse reactions of methotrexate include nausea, vomiting, jaundice, hair loss, reddening of the skin, thrombocytopenia, long-term users need to go to the hospital for regular review, and the use of the product is prohibited for those who are highly allergic to methotrexate, extreme systemic failure, malignant fluid, pregnant women, and breastfeeding women. Precautions: The mutagenicity, teratogenicity and carcinogenicity of this product are milder than that of alkylating agents, but there is a potential risk of secondary tumors after long-term use. The effects on reproductive function, although also less than alkylating agents, can also lead to amenorrhea and sperm reduction or lack of spermatozoa, especially in the long-term application of larger doses. Therefore, long-term use of methotrexate is not recommended. Patients requiring methotrexate are advised to consult the relevant department.