This document summarizes information about rheumatoid arthritis (RA), including its risk factors, potential treatments, and the drug methotrexate. RA is an autoimmune disease that affects about 0.5% of adults worldwide and predominantly impacts women. Genetic and environmental factors are thought to trigger RA. Methotrexate is currently considered the primary treatment for RA and is administered to around 70% of patients with the disease. The document also outlines a three-phase treatment plan for RA and discusses the use of methotrexate both orally and via injection.