<正> Objective: To investigate whether bacterial DNA involving in the pathogenesis of systemic inflammatory response syndrome （SIRS） and possible mechanism. Methods: Escherichia coli DNA （EC DNA） was extracted from Escherichia coli 25922 with alkaline lysis method. The mice mortality was observed after EC DNA was injected into mice via caudal vein. The changes of serum TNF-α and IL-6 levels in rats were measured with ELISA after rats were given EC DNA. Calf thymus DNA and lipopolysaccharide （LPS） were used as the control

respectively. Results: EC DNA led mice to death with notable dose-effect relationship （LD50 = 11. 51 mg/kg）

but CT DNA didn’t. The peak level of TNF-α was lower in EC DNA group than in LPS group （P<0. 05）

though the former reaching the peak I h earlier than the latter. However

they had coordinate ability to induce IL-6 release in rats

and no significant difference was seen in serum IL-6 peak level between 2 groups. Conclusion: EC DNA leads mice to death

and induces the increases of s