We treated a patient who experienced motor weakness and sensory change on left lower extremity after thoracic sympathetic ganglion block with pure alcohol. The following factors were suspected of contributing to neurologic complication: (1) ischemia of spinal cord, (2) infection, (3) re-expression and aggravation of pre-existing neurologic disease, (4) improper position. Patient spontaneously recovered from neurologic complication with conservative therapy.