Methotrexate is an anti-folate antitumor drug, which is an orange-colored crystalline powder. It mainly inhibits the growth and reproduction of tumor cells through the inhibition of dihydrofolate reductase, which hinders the synthesis of tumor cells. The side effects include: 1. gastrointestinal reactions, nausea, vomiting, diarrhea, etc. 2. bone marrow suppression, mainly manifested as a decrease in white blood cells. 3. a large number of applications can cause elevated glutamate transaminase and drug-related hepatitis; a small number of persistent applications can cause cirrhosis. 4. kidney damage, hematuria, proteinuria, etc. 5. early use in pregnancy can cause teratogenesis, and a few patients have delayed menstruation and reduced reproductive function. 6. 6. Hair loss, dermatitis, hyperpigmentation and drug pneumonia can also occur.