Two types of sympathectomy are common today, the lumbar and the cervicothoracic. It is a simple operation with extremely low mortality and morbidity although the patients are frequently of an advanced age. 8--10 days after the operation pains may occur, especially at night. The authors observed them in 3--15% of cases after lumbar sympathectomy, more rarely after cervicothoracic sympathectomy. The pains usually disappear after a few weeks or months. Sexual disturbances may occur in about 10--15% of young men. Therefore in these patients the first two lumbar ganglia should be spared. Arterial obstructions above all arteriosclerotic occlusions are the most important and most frequent indications for surgery of the sympathetic nervous system. Statistics from the Strasburg Hospital yielded a total of 56% good and very good results in 666 lumbar sympathectomies, and 31.2% successes even in Fontaine's stage IVa.