After some preliminary remarks of a biochemical and pharmacological nature, the authors have started a clinical study to test the antiinflammatory activity of the S-adenosyl-methionine (SAMe). An open trial, carried out on 90 patients with severe degenerative arthropathies has shown that 30 mg SAMe intravenously twice a day for 14 days have a marked anti-inflammatory effect a rather term and no side-effects. In a "double-crossover" investigation, SAMe was next compared to indomethacin by i.m. administrations to 15 arthropathic patients. The therapeutic responses of the two drugs proved exactly alike, whereas the side-effects following indomethacin administration were not present after SAMe. In 9 patients affected with rheumatoid arthritis administrations of SAMe have proved less effective, although some clinical parameters showed improvements.