Objective To observe the effect of Chenpi volatile oil and water fired Chenpi on the in vivo intestinal smooth muscle movement of rabbits and transitional composition in the blood plasma. Methods We used the experiment method of in vivo intes- tine of rabbits and HPLC. Results Chenpi volatile oil could reduce the intestinal contraction frequency. Water fired Chenpi could make intestinal amplitude and frequency reduce. New compound was not discovered in blood plasma after giving Chenpi volatile oil to rabbits. One species of prototype components from water fired Chenpi could be seen. The time i...