Objective To investigate the effect of remifentanil preconditioning on hypoxia-reoxygenation (H/R) injury to human hepatocytes.Methods Human HL7702 hepatocytes were cultured in vitro and randomly divided into 6 groups (n =16 each):control group (group C),H/R group,preconditioning with low,median and high concentrations of remifentanil groups (groups RP1-3) and normal saline group (group NS).H/R was produced by 8 h exposure of cells to 94％ N2-5％ CO2-1％ O2 in glucose-free DMEM liquid culture medium followed by 4 h reoxygenation.Remifentanil with the final concentrations of 0.5,5.0 and 50.0 ng/ml were added before hypoxia in groups RP1-3 respectively.Normal saline equal to the volume of remifentanil was added before hypoxia,the culture medium was replaced with glucose-free DMEM liquid culture medium 1 b later and H/R was produced in group NS.At 4 h of reoxygenation,the cell viability was measured by MTT,and activities of alanine aminotransferase (ALT),aspartate amino transferase (AST) and lactic dehydrogenase (LDH) in the culture medium and malondialdehyde (MDA) content in the cells were determined.The cell morphology was also examined.Results Compared with group C,the cell viability was significantly decreased,the activities of AST,ALT and LDH in the culture medium and MDA content in the cells were significantly increased in the other groups (P ＜ 0.05).Compared with groups H/R and NS,the cell viability was significantly increased,the activities of AST and LDH in the culture medium and MDA content in the cells were significantly decreased in group RP2 (P ＜ 0.05),and no significant change was found in the parameters mentioned above in groups RP1 and RP3 (P ＞ 0.05).The degree of damage to the hepatocytes was significantly reduced in group H/R compared with group RP2,and comparable in groups H/R,RP1 and RP3.Conclusion Preconditioning with the median concentration of remifentanil (5 ng/ml) can reduce H/ R injury to the human hepatocytes,while the low (0.5 ng/ml) or high (50 ng/ml) concentration of remifentanil has no such effect.