We report a case of Complex Regional Pain Syndrome (CRPS) complicated with liver dysfunction during continuous epidural mepivacaine treatment. A forty-five-year old woman was admitted to our hospital with pain of the right hand. After a diagnosis of CRPS, she received continuous epidural block with 1% mepivacaine and intravenous regional sympathetic block using 10mg guanethidine. Gradually, her pain almost disappeared 3 weeks after these treatments. However, on the 25th hospital day, she complained of epigastric discomfort and general malaise. The serum GOT and GPT levels increased to 130 and 408IU/l respectively. The continuous epidural block and drug therapy were immediately discontinued. The rise in transaminases persisted for a month after general malaise disappeared. The increase of serum transaminases and eosinophilia was most suggestive of drug-induced liver dysfunction. Mepivacaine was suspected as the cause owing to the course of laboratory data. It is concluded that liver function tests are essential during continuous epidural block.