Dexmedetomidine, a highly selective α2-adrenergic agonist, can reduce the consumption of other sedative and antinociceptive drugs and provide sufficient sedative effects with minimal respiratory side effects. In addition, dexmedetomidine gradually has gained popularity in the field of critical care. Preemptive administration of dexmedetomidine has shown to be protective against inflammation, intestinal, renal, and myocardial injuries in animal and human studies. Dexmedetomidine is also used as an anesthetic adjuvant during surgery to offer good perioperative hemodynamic stability and an intraoperative anesthetic-sparing effect. Perioperative use of dexmedetomidine can reduce intestinal and hepatic injury after hepatectomy with inflow occlusion under general anesthesia. However, whether or not it can exert protective effects on the above-mentioned organs, especially intestine, after cardiac surgery remains unclear. The aim of this study is to evaluate the effects of dexmedetomidine on intestinal, hepatic, and other organ injury in patients receiving cardiac surgery with CPB.