This is a single center, randomized, double-blinded, controlled clinical trial.The purpose of this study is to compare the effect of TEAS pretreatment with single acupoint or two acupoints for postoperative nausea and vomiting in patients undergoing laparoscopic operation.

Patients were randomly assigned to four groups, receiving TEAS 30 minutes before induction.The stimulation was applied until the end of the operation. Postoperative nausea and vomiting was recorded 30 minute, 2 hour, 6 hour and 24 hour after the operation. The adverse events were recorded as well.

Inclusion Criteria:

1. ASA I-III
2. Aged 18 to 65 years old
3. Scheduled for general anesthesia
4. BMI index is between 18 to 30
5. Informed consented

Exclusion Criteria:

1. ASA IV

2. Hypertension that is not controlled

3. Severe hepatic or renal dysfunction

4. Ever had received electrical stimulation treatment

5. Severe systemic infection

6. With contraindications to the use of TEAS, such as skin damage or infection at the acupoints

7. For any reason one can not cope with the studies, such as the following:

   language comprehension, mental illness

8. Participate in the other clinical trial 3 month before the enrollment