ABSTRACT
This experimental study was carried out to evaluate the possible therapeutic effects of melatonin in rheumatoid arthritis and its interaction with indomethacin. The study was carried out on rats in which rheumatoid-like arthritis were induced experimentally by an intradermal injection of a total volume of 0.1 ml of cold emulsion consisting of native type II collagen and complete Freund's adjuvant. A booster dose was given after three weeks. It could be concluded that melatonin had an immune stimulant effect enhancing the immune system and its use in autoimmune diseases such as rheumatoid arthritis exaggerated arthritic manifestations. Also, a combined administration of melatonin and indomethacin had no therapeutic effect on patients suffering from rheumatoid arthritis