Corilagin (CRN) isolated from Euphorbia helioscopia as rheumatoid arthritis drug. CRN was medicated to the abdominal cavity of collagen induced arthritis (CIA) mice that was an animal model for rheumatoid arthritis and its effects on incidence and arthritis index were studied. The results were as folllows; It was exhibited that medicating corilagin inhibited the infiltration of activated T lymphocytes into an inflammatory joint. The production of IgG and IgM that were RF (rheumatoid factor) and inflammatory cytokine, IL-6 and $TNF-{alpha}$were reduced. After measuring $IFN-{gamma}$and IL-4, it was found that it was shifted into Th2 immune response as increasing in IL-4. After liver function test, studies on liver poisoning of AST/ALT should be continued.