Endoscopic Thoracic Sympathectomy (ETS) is a surgical procedure where certain portions of the sympathetic nerve trunk are destroyed. ETS is used to treat hyperhidrosis, facial blushing, Raynaud's disease and reflex sympathetic dystrophy. By far the most common complaint treated with ETS is palmar hyperhidrosis, or "sweaty palms". In this disorder, the palms may constantly shed so much sweat that the affected person is unable to handle paper, sign documents, keep clothes dry, or shake hands. The result is often social phobia so severe as to be disabling. Sympathectomy physically destroys some tissue anywhere in either of the two sympathetic trunks. The most common area targeted in sympathectomy is the upper thoracic region, that part of the sympathetic chain lying between the first and fifth thoracic vertebrae. In addition to the normal risks of surgery, such as bleeding and infection, sympathectomy has several specific risks, such as adverse changes in how nerves function. With ETS the results are very rewarding in relation to palmar hyperhidrosis, with the disappearance of the symptoms in all cases. Compensatory sweating, the most common side effect usually well tolerated, and the satisfaction index is quite high, so ETS is popular among patients and physicians. Immediate and short-term results of Endoscopic Thoracic Sympathectomy (ETS) for primary hyperhidrosis are excellent. Adverse effects have been identified clearly and are supposed to decrease with time. Compensatory Hyperhidrosis (CH) is the most common and distressing complication for sympathectomy, and it is the "quality marker" of ETS. It is characterized by the postoperative appearance of excessive perspiration in regions of the body where it had not been previously observed.