Methotrexate is an anti-metabolic chemotherapy drug, methotrexate is currently used clinically for the treatment of acute leukemia, as well as head and neck squamous carcinoma, breast cancer, lung cancer and other solid tumors, the main side effects of methotrexate after application are as follows: 1, bone marrow suppression, which is a common adverse reaction after methotrexate application, adverse reactions affect the dosage of methotrexate, clinically mainly manifested as white blood cells, the This is also a common side effect after methotrexate application, mainly manifested as nausea, vomiting, diarrhea, mouth ulcers, etc. Some may have the clinical manifestation of gastritis; 3. Liver function damage, many methotrexate applicants are prone to liver function damage, and chronic liver fibrosis can occur in serious cases.