In this experiment, the acute hemorragic necrotic pancretitis(AHNP) animal was pretreated by abdominal cavityinjection of recombinant humantumor necrosis factor (rhTNF) or by selective decontamination of digestive tract (SDD) with the use of tybrarmycine, amphotericinum Band polymyxine B orally plus a small dose of polymyxine B by hypodermic injection. The results showed that using exogenous TNF to treat AHNP can reduce mortality of AHNP rats. The mechanism may be that exogenous TNF can induce the tolerance of the host organ(s) to endogenous TNF. SDD plus a small dose of polymyxine B by hypodermic injection can suppress G baeteria grouth and reduce the production of endotoxin in the gut ; and polymyxine B can directly antagonize to the endotoxin of blood, reducing bloodendotoxin and TNF level. The results suggest that SDD can be used to treat AHNP.