Objective: To explore the effect of baicalin(BC) and dexamethasone(DXM) on interleukin 1β(IL 1β) and tumor necrosis factor α(TNF α) in brain tissues of infectious brain edema. Methods: The infectious brain edema model induced by pertussis bacilli(PB) was used. Brain water content(WC), content of Na + and the levels of IL 1β, TNF α were determined, and the morphological changes were observed under the light microscope. Results: The results showed that the levels of WC, Na +, IL 1β and TNF α in group PB were higher than those in group of normal saline(NS) (P<0.01). And they were lower in groups BC and DXM than those in group PB(P<0.05). In groups BC and DXM, there were no significant difference in the contents of water, Na +, IL 1β and TNF α(P>0.05). The water contents were positive linar correlated with IL 1β or TNF α(P>0.05). The water contents were positive linear correlated with IL 1β or TNF α contents(r=0.9381,0.8349,P<0.01). The structure of brain tissues in group NS was normal. In group PB, there were severe edema in brain tissues. In groups BC and DXM, the edema of brain tissues was reduced. Conclusions: The results suggest that the protective effect of BC and DXM against infectious brain edema were similar, the mechanism may be associated with the reduction of TNF α and IL 1β. <