[Objective] To study the effects of essential oil from Chimonanthus praecox on rat adjuvant arthritis and their mechanisms. [Method] Rats were divided randomly into normal control group, model control group, positive drug group and high-, middle- and low-dosage groups of essential oil from C. praecox (10.0, 5.0 and 2.5g/kg crude drug). Adjuvant arthritis (AA) rat model was established by subcutaneous injection of Freund’s adjuvant (FCA) except the normal group. Drugs were given by oral gavage for 21d continuously from the modeling day. The anti-arthritic effects and mechanism of essential oil from C. praecox in Guizhou against RA were studied through observing the paw swelling, viscera index pathological changes and levels of interleukin 1β(IL-1β) and tumor necrosis factor α(TNF-α) after medication. [Result] The essential oil from C. praecox could effectively inhibit the rat paw edema, compared with model group. But it had no significant effects on the immune organs. The contents of IL-1β and TNF-α in the serum of AA rats decreased significantly compared with model group. [Conclusion] The essential oil from C. praecox had certain therapeutic effects on rat adjuvant arthritis, and its mechanism might be related to the reduction of cytokine generation. [Objective] To study the effects of essential oil from Chimonanthus praecox on rat adjuvant arthritis and their mechanisms. [Method] Rats were divided randomly into normal control group, model control group, positive drug group and high-, middle- and low-dosage groups of essential oils from C. praecox (10.0, 5.0 and 2.5 g / kg crude drug). Adjuvant arthritis (AA) rat model was established by subcutaneous injection of Freund’s adjuvant (FCA) except the normal group. The anti-arthritic effects and mechanism of essential oil from C. praecox in Guizhou against RA were studied through observing the paw swelling, viscera index pathological changes and levels of interleukin 1β (IL-1β) and tumor [Result] The essential oil from C. praecox could effectively inhibit the rat paw edema, compared with model group. But it had no significant effects on the immune organs. The contents o f IL-1β and TNF-α in the serum of AA rats decreased significantly with the model group. [Conclusion] The essential oil from C. praecox had certain therapeutic effects on rat adjuvant arthritis, and its mechanism might be related to the reduction of cytokine generation.