BACKGREOUND: The sympathetic investigations during thoracic sympathectomy are essential to an adequate sympathectomy that will lead to sufficient and lasting relief of palmar hyperhidrosis. The measurement of palmar skin temperature has been used as an indicator of success of transcutaneous chemical thoracic sympathectomy. We measured intraoperative palmar skin temperature to know whether it can be used as a same purpose in the endoscopic thoracic sympathectomy under general anesthsia. METHODS: Fifteen patients (18 to 25 years old) with palmar hyperhidrosis underwent endoscopic thoracic sympathectomy under general anesthesia. The palmar skin temperature was measured with a skin probe of a thermometer applied on the both index finger tips. The palmar skin temperature was monitored continuously from the beginning of anesthesia to the complete arousal. RESULTS: The palmar skin temperature increased significantly by about 3 degrees C just after induction. There was no significant difference in the palmar skin temperature between just before sympathectomy and soon after sympathectomy during the endoscopic thoracic sympathectomy. CONCLUSIONS: Intraoperative measurement of palmar skin temperature can not indicate a definite sympathectic denervation during the endoscopic thoracic sympathectomy under general anesthesia.