One of the main goals of sympathetic blocks is to determine how much a patient’s pain is sympathetically mediated. However, even though patients may have a diagnosis of complex regional pain syndrome (CRPS) and what appears to be sympathetically-mediated pain, they may not be responsive to sympathetic blockade. The list of indications for sympathetic blocks is long, and much of the evidence does not include randomized clinical trials. Common syndromes that are amenable to the use of sympathetic blocks include: CRPS, phantom limb pain, angina, and vascular insufficiency (i.e. Raynaud’s syndrome, diabetes). Lumbar sympathetic block is indicated for sympathetically mediated pain in the lower extremities and pelvis. Superior hypogastric plexus block is indicated for pelvic viscera pain, which can cover sympathetically-mediated pain of the bladder, uterus, rectum, vagina and prostate.