1.The following preparations should be made before using methotrexate: assessment of risk factors for methotrexate adverse reactions (such as alcohol consumption, etc.); patient education; testing of routine blood, liver and kidney function, albumin, AIDS antibody, hepatitis B markers, hepatitis C antibody, blood glucose, lipids and pregnancy test; chest X-ray (before and within several years after the drug), etc. 2. The first oral dose of methotrexate is often 5mg-7.5mg once a week. If the efficacy is good and tolerable, the dose can be increased by 2.5mg every 2-4 weeks to a maximum of 15-20mg once a week. If the efficacy is poor or not tolerated, intravenous administration can be considered. 3.The combination of at least 5 mg of folic acid orally every week, taken on the 3rd day after using methotrexate, can both reduce methotrexate side effects and maintain methotrexate efficacy. 4. When starting methotrexate or when its dose is increased, liver and kidney function and blood picture should be tested once every 1 month to 1.5 months. After the dose of methotrexate is stabilized and the indexes are stable, the testing interval can be extended to once every 1-3 months. It is necessary to know whether there are any adverse reactions to methotrexate at each visit and to assess whether there are any risk factors for adverse reactions. 5. When the transaminase level increases to more than 3 times the upper limit of normal, the drug should be discontinued immediately and the transaminase [Med. Academic. Net search. After the aminotransferase level returns to normal, restart treatment with low-dose methotrexate. However, if the aminotransferase level continues to be more than three times the upper limit of normal, the methotrexate dosage should be adjusted. If the transaminase level continues to be more than 3 times the upper limit of normal after stopping methotrexate, other causes should be found. 6.If there is no adverse reaction with methotrexate, it can be used for a long time. 7. Patients with no history of condition-improving drug applications have a better efficacy/risk ratio with methotrexate alone. When it is difficult to control the disease with methotrexate monotherapy, it can be combined with other disease-modifying drugs. 8. Methotrexate helps to reduce the hormone dose and can also be used in the treatment of rheumatic polymyalgia and giant cell arteritis. In addition, it can also be used for the treatment of systemic lupus erythematosus and dermatomyositis (including juvenile). 9.For patients with rheumatoid arthritis who need surgery, methotrexate can be used non-stop before surgery. 10.Methotrexate needs to be stopped for both men and women in the first 3 months of pregnancy. Methotrexate is prohibited during pregnancy and lactation.