OBJECTIVE Inadequate perfusion in splanchnic organs and especially in the gut during acute burn period has been reported in many conventionally "successfully" resuscitated patients, but the mechanisms still remain unclear and its early preventive measures need to be further studied. The aim of this study is to evaluate the role of endothelin and nitric oxide in gut ischemia. METHODS Eighteen male pigs were randomly assigned to one of the three groups: group C, a sham burn group that was subjected to all surgical procedures except burn; group B, sustained 30% TBSA cutaneous thermal burn; Group N, NO donor (C87-3754) was given intravenously (0.0125 mg.kg-1.min-1) at the beginning of resuscitation. RESULTS In group B, PVF decreased rapidly after burn, and did not recover in the observation period (72 h), ET levels in portal blood and intestinal tissue elevated contrary to the changes in NO. In group N, PVF was higher than in group B. CONCLUSION 1. Changes in ET and NO may influence the protal blood flow. 2. NO donor was proved to be beneficial in improving GI tissue perfusion by releasing NO.