BACKGROUND: Propofol is an intravenous anesthetic agent, which has a protective effect on cardiovascular and CNS toxicity of local anesthetics compared with an inhalational agent. Also lipids have a has protective effects on local anesthetic cardiovascular toxicity. So, we had questioned that the protective effect on local anesthetic toxicity comes from the lipid solvent of propofol or propofol itself. METHODS: Eighteen healthy rabbits, weighing 3.0 Kg, were divided into three groups during continuous intravenous infusion of bupivacaine: the control group received normal saline (n = 6), the propofol group received propofol (n = 6), and the intralipid group received intralipid (n = 6). The changes in mean arterial pressure, heart rate and the electrocardiogram were observed during the continuous intravenous infusion of bupivacaine. RESULTS: The onset time of QRS widening and dysrhythmia was significantly prolonged in the propofol group compared with the control and intralipids group. The time required for 25% and 50% decrease in mean arterial pressure and heart rate during bupivacaine infusion was significantly prolonged in experimental groups compared with the control group. In the propofol group compared with the intralipids group, the time required for a 25% and 50% decrease in mean arterial pressure and heart rate were prolonged. CONCLUSIONS: This study suggests that infusion of propofol protection on cardiac toxicity of intravenous infusion by an bupivacaine, the dosage for sedation without cardiovascular adverse effects, is more profound than intarlipids.