Methotrexate is sensitive to hydrolysis, oxidation and light. Insoluble in water. Methotrexate decomposes in very acidic or alkaline conditions. Methotrexate is incompatible with strong oxidizing agents and strong acids.

Methotrexate is a drug used for the treatment of cancer, also known as cytotoxic drugs. In order to reduce its cytotoxicity, it can be used in conjunction with calcium leucovorin. It is primarily used for the treatment of acute leukemia (acute lymphocytic leukemia), breast cancer, malignant mole and choriocarcinoma, head and neck cancer, bone cancer, leukemia, spinal cord meningeal infiltration, lung cancer, reproductive system cancer, liver cancer, refractory psoriasis vulgaris, dermatomyositis, body myositis, ankylosing spondylitis inflammation, Crohn's disease, psoriasis and psoriatic arthritis, Behcet's disease and autoimmune disease. Methotrexate is an immuno suppressant and can be used for easing the process of rheumatism with a particularly excellent efficacy in treating synovial inflammation of rheumatoid arthritis and is the most frequently used drugs for treating rheumatoid diseases.