Interventions for making a diagnosis in the patient with chronic pain can present certain therapeutic challenges. The etiology and type of pain is not always clear and diagnostic or therapeutic blocks can be of value with injectable agents. Injectables given are steroids, local anesthetics, hyaluronacid, and neurolytic agents. Local anesthetics are safe, and complications due to use of local anesthetics are rare and depend on the skills of the practitioner performing any block, the correct indication and patient selection, anatomy, and pharmacology knowledge, as well as the technique and equipment used. Over the years, development of the use of neurolytic agents has become increasingly diverse: the combination of phenol and alcohol, application of glycerol, ammonium salts, hypertonic saline, and chlorocresol increasing the variety of neurolytic agents. A serious complication related to the administration of 50% alcohol following intraoperative celiac plexus injection resulted in permanent paraplegia.