Methotrexate for the treatment of rheumatoid arthritis is taken orally at 5mg to 10mg/day once or twice a week, and methotrexate for injectable use is injected intramuscularly at 5mg to 15mg for the first time, once a week. Methotrexate can be used to treat rheumatoid arthritis, mainly through oral tablets or injectable medication. When used for the treatment of rheumatoid arthritis, oral tablets of methotrexate, a course of safe amount of 50mg to 100mg, adults 5mg to 10mg once a day, once or twice a week. Injectable medication is mainly used for the treatment of refractory rheumatoid arthritis, the first dose of 5 to 15mg intramuscular injection, once a week. Subsequent weekly increments of 5mg to 25mg (maximum dose) are allowed. It should be noted that the application of methotrexate may cause adverse reactions such as nausea, anorexia, oral erosion, vomiting, diarrhea, alopecia, elevated aminotransferases, pneumonitis, hepatic fibrosis and hematological abnormalities. Methotrexate is contraindicated in women during pregnancy, hepatic and renal insufficiency or with hematologic disorders. It should be noted that folic acid supplementation is needed when using methotrexate treatment. When methotrexate is needed for the treatment of rheumatoid rheumatism, it is recommended to consult the rheumatology and immunology department in time, and the treatment should be carried out under the guidance of the doctor, and should not be used without authorization.