AIM: To investigate the effect of shenfu injection on gastrointestinal microcirculation after myocardial ischemic-reperfusion (IR) injury in rabbits and probe into the mechanism. METHODS: Forty healthy flap-eared white rabbits were randomly divided into 4 groups: IR injury control group (group I), shenfu injection 5 mL/kg per h group (group H), shenfu injection 10 mL/kg per h group (group III) and shenfu injection 20 mL/kg per h group (group IV). The four groups were treated with Lactated Ringer's solution, shenfu injection 5, 10, and 20 mL/kg per h were infused intravenously 30 min before experiment respectively. The values of hemodynamics [mean arterial pressure (MAP), heart rate (HR), gastric intramucosal partial pressure of carbon dioxide (PCO2), blood gas analysis and pH] were measured and compared with those before myocardial ischemia, 60 min after myocardial ischemia and 60, 90, and 180 min after reperfusion. RESULTS: The MAP, HR and gastric intramucosal pH were (70.50 +/- 4.50) kPa, (165 +/- 14) beats per min, 7.032 +/- 0.024 in group 1 60 min after myocardial ischemia, which were significantly decreased compared with those before myocardial ischemia (88.50 +/- 9.75 kPa, 217 +/- 18 beats per min, 7.112 +/- 0.0351 P < 0.05). The MAP, HR and gastric intramucosal pH were significantly decreased in group 1 60, 90, and 180 min after reperfusion (61.50 +/- 5.25 kPa, 133 +/- 31 beats per min, 6.997 +/- 0.025) compared with those before reperfusion respectively (P < 0.05), whereas the values were insignificantly different in groups II, M or IV after reperfusion, compared with those before reperfusion, and there were no significant differences between groups II, III, and IV after reperfusion. CONCLUSION: Pre-infusion of shenfu injection has a protective effect on gastrointestinal microcirculation after myocardial IR injury in rabbits, in a dose independent manner. (C) 2006 The WJG Press. All rights reserved.