BACKGROUND: This study was performed to evaluate the effects of pre-emptive subdiaphragmatic instillation of lidocaine before pneumoperitoneum on postoperative pain following a laparoscopic cholecystectomy (LC) and also to evaluate it's effect on the changes of blood pressure during an operation. METHODS: Thirty-three relatively healthy patients for an LC were allocated into the two groups. after the induction of general anesthesia with sodium thiopental, vecuronium, nitrous oxide and enflurane (1-2 vol%), 0.2% lidocaine 200 ml was subdiaphragmatically instilled 10 min before pneumoperitoneum in the lidocaine group (n = 15), and normal saline in the control group (n = 18). The changes of the systolic and mean arterial pressure (SAP and MAP), postoperative pain score, and the number of analgesics used during the postoperative 24 h were compared between two groups. RESULTS: The pain scores at postoperative 1, 3, 6, 12, 18 and 24 h and the number of analgesics used were significantly low in the lidocaine group compared to the control group (P<0.01). The elevations of SAP and MAP during pneumoperitoneum were significantly attenuated in the lidocaine group (P<0.01). CONCLUSIONS: This data suggests that subdiaphragmatic instillation of lidocaine before pneumoperitoneum is effective in the control of postoperative pain following an LC and also effective to attenuate the elevation of blood pressure during pneumoperitoneum. However, further study is needed to evaluate the safety of these methods before recommendation of routine use.