Objective: To discuss the antipyretic mechanism of Buzhong Yiqi Tang. Method: The rats were assigned into the normal group

spleen-qi deficiency with fever group

Buzhong Yiqi Tang group

10 rats in each group. The rats of spleen-qi deficiency with fever group and Buzhong Yiqi Tang group were treated with excess fatigue plus out of constant diet to copy spleen-qi deficiency rat model. The body temperatures were measured each week. From the 18th day

Buzhong Yiqi Tang group rats were fed with medicine 6.83 g·kg-1. The ones of the normal group and spleen-qi deficiency with fever group with physiological saline for 5 days. At 8:00 am on the 22th day

the rats of Buzhong Yiqi Tang group and the spleen-qi deficiency with fever group were respectively intraperitonealy injected with lipopoly saccharide(LPS

80 μg·kg-1) to induce fever. The rats of the normal group with physiological saline. The rectal temperature was measured at 30

60

120

180

220 min after ip LPS and the mean body temperature curve draw. Then cAMP and PGE2 in hypothalamus were measured. Result: Compared with the normal group

the rectal temperature curve of spleen-qi deficiency with fever group rises significantly at every research spot (P<0.05 or P<0.01). Compared with the spleen-qi deficiency with fever group

the temperature

cAMP and PGE2 of Buzhong Yiqi Tang group were obviously decreased(P<0.05 or P<0.01). Conclusion: Buzhong Yiqi Tang has antipyretic effect on the spleen-qi deficiency with fever model. Its antipyretic mechanism may be connected with reducing central pyrexia amboceptor PGE2 and cAMP.