Rheumatoid arthritis is a chronic, inflammatory, autoimmune disease of the joints, primarily affecting the articulating joints of the hands and feet. This ailment is a debilitating disease affecting approximately 1% of the world's population. Joint swelling, tenderness, and the erosion of the synovial lining of affected joints are common symptoms of rheumatoid arthritis. Joint inflammation is caused by the immune system invading the tissues surrounding the joint, while the damaging effects to the joint are due to the secretion of enzymes and chemicals that break down the surrounding tissues. Presently, the disease is considered incurable, but a large host of drugs have been found to help alleviate the effects of rheumatoid arthritis. Plasma carboxypeptidase B and glycosaminoglycans are reviewed as potential causes of rheumatoid arthritis. Possible mechanisms by which rheumatoid arthritis progresses through the body are also reviewed, as are the effects of alpha-1 antitrypsin protein, D-penicillamine, and methotrexate treatments. Methotrexate is emphasized due to its common usage and efficacy.