Percutaneous neurolysis of upper thoracic sympathetic ganglion was performed in 40 patients by simultaneously injecting 3 ml of pure alcohol into the T2 and T3 levels after 3 ml of injection of local anesthetic agent on the same sites. Using a skin temperature probe, finger tip temperatures were measured on the index finger ipsilateral to the nerve block before block, 15 and 30 minutes after test block, and 30 minutes after alcohol block. Alcohol block was performed immediately after 30 minutes test block. Finger tip temperatures obtained at 30 minutes post alcohol block and test block and the differences in the temperatures measured before and 30 minutes after alcohol block were shown to be statistically important as potential indicators for prediciting long term outcome of therapy for palmar hyperhidrosis using this technique. These results demonstrate that the palmar temperature monitoring method is sufficiently sensitive to predict the outcome of nerve block during and after thoracic sympathetic ganglion block.