Objects: We evaluated the effectiveness of transcutaneous electrical acupoint stimulation ( TEAS) at the P6 acupoint for prevention of postoperative nausea and vomiting in patients undergoing supratentorial craniotomy. Methods: The study population was patients aged 20 to 60 years who underwent supratentorial craniotomy under general anesthesia. Exclusion criteria were obesity, diabetes mellitus, and a history of motion sickness, postoperative nausea and vomiting, or smoking. Patients were randomized into 2 groups: stimulation and control. In the former, transcutaneous stimulation electrodes were placed at the right P6 acupoint. In controls, electrodes were positioned at a nonacupoint site. Patients received a standard general anesthesia. Ondansetron was given as a routine antiemetic treatment for each patient before skin closure. Postoperatively, metoclopramide (10 mg, i.v.) was administered as a rescue antiemetic. Result: Forty patients received TEAS and 40 were controls. In the TEAS group, 18% of patients had nausea compared with 37% of the controls. The cumulative prevalence of vomiting was 12.5% with acustimulation and 32.5% in controls (P < 0.05). The prevalence of nausea, vomiting was significantly lower with TEAS at the P6 acupoint. Conclusions: TEAS at the P6 meridian points is an effective adjunct to standard antiemetic drug therapy for prevention of nausea and vomiting in patients undergoing supratentorial craniotomy.