¡¾Abstract¡¿ AIM: To study the effect of nimodipine on the anesthetic action of isoflurane. METHODS: Twenty patients with ASA physical status I-II, scheduled for cholestectomy under general anesthesia, were randomly divided into two groups: nimodipine group (Group A) and placebo group (Group B), with 10 cases in each group. Before anesthesia, 0.5 ¦Ìg/(kg¡¤min) of nimodipine was intravenously administered to the patients in Group A, and normal saline was given to the patients in Group B. M1025A Anesthetic Gases Concentration Monitoring Equipment was used to monitor the concentration of isoflurane in endª²tidal gas (FETISO). Blood pressure, heart rate and the consumption of isoflurane during anesthesia were recorded in this study. Blood was sampled for the determination of plasma corticol content and blood sugar level. RESULTS: 0.5 ¦Ìg/(kg¡¤min) of nimodipine had no significant effect on the blood pressure and heart rate. Mean FETISO and isoflurane consumption in Group A were (11¡À4) mL/L and (4.1¡À0.5) mL/h respectively, significantly lower than those in Group B [Mean (18¡À3) mL/L and (6.9¡À1.0) mL/h respectively, P<0.01]. CONCLUSION: 0.5 ¦Ìg/(kg¡¤min) of nimodipine can markedly reduce the consumption of isoflurane during general anesthesia. ......