Objective To study the effects of lidocaine on inflammatory mediators and myocardial enzymes in patients undergoing off-pump coronary artery bypass grafting (OPCAB).Methods Twenty patients underging OPCAB were randomly divided into 2 groups of L and C with 10 cases each. After anesthesia induction, group L was given a bolus of lidocaine 2 mg/kg, which was followed by an infusion of lidocaine 2 mg·kg~(-1)·h~(-1) till the end of operation. Group C was given normal saline instead of lidocaine as the control. Blood samples were taken for the measurements of TNF-a, IL-8, SOD, MDA, cTnⅠ, CK-MB and MYO. The hemodynamics, early postoperative clinical informations and ICU and hospital stay were recorded. Results The increases of TNF-α and IL-8 were significiently less in group L than those in group C(P<0.01 or P<0.05). MDA at 24 h after operation was higher in group C than that in group L(P<0.05). The increases of CK-MB and cTnⅠ at 24 h and 48 h after operation were significiently less in group L than those in group C(P<0. 01 or P <0. 05). The ICU and hospital stays were shorter in group L than those in group C(P<0. 05). Conclusion Continuous infusion of lidocaine during OPCAB can decrease the inflammatory mediators and myocardial enzymes and protect the myocardium.