Methotrexate is prescribed for treating certain types of cancer such as eukemia, bladder cancer, stomach cancer, breast cancer. It also helps to treat rheumatoid arthritis, psoriasis and psoriatic arthritis. When this tablet is used to treat rheumatoid arthritis, It acts by suppressing the immune system reducing inflammation. When used to treat cancer, this medication acts by blocking an enzyme process in cancer cells hence they cannot grow.