The authors hypothesize that palmar hyperhidrosis is a systemic manifestation of abnormal sudomotor function; consequently, thoracoscopic sympathectomy to alleviate symptoms in the hands may result in heat dissipation because sweating is transferred to other sites. To investigate this phenomenon and to determine whether it adversely affects patient satisfaction, a standard questionnaire was administered to 626 patients who underwent sympathectomy at a university-associated public hospital between 1991 and 1998; only patients treated at least 6 months before questionnaire distribution were included in the study. Replies were received from 336 (53.7%) individuals. The surveyed patients underwent bilateral T2, T3 (palmar sweating), or T3, T4 (axillary sweating) sympathectomy by a standard video-assisted transthoracic technique. Main outcome measures included the incidence of dry hands, compensatory sweating, chest pain, upper-limb muscle weakness, shortness of breath, and gustatory phenomena; in addition, patient perception of the success of the surgical procedure was assessed. After sympathectomy, 97.3% (P < 0.0001) and 29.2% (P < 0.001) of patients reported significant improvement in palmar hyperhidrosis and axillary sweating, respectively. Postsurgery, severe compensatory sweating was experienced in 90% of patients (P < 0.0001). The sites of compensatory sweating were the back (75%), abdomen (51%), feet (23%), groin and thigh (13%), chest (13%), and axillae (8%). Transient whole-body sweating for no apparent reason was experienced in 30% of patients. Thirty-seven patients (11%) regretted having undergone the surgical procedure. In contrast, 25% and 64% of patients were either satisfied or very satisfied with the outcome of the procedure. From the survey results, the authors conclude that palmar hyperhidrosis is a systemic manifestation of abnormal sudomotor function and that thoracic sympathectomy may alleviate symptoms in a large proportion of patients. However, for some individuals, compensatory sweating may prove to be an equally troublesome handicap. Because the occurrence of severe compensatory sweating is unpredictable, a reversible sympathectomy may be desirable.