Neural therapy is a treatment system to relieve chronic pain and illness through the injection of local anesthetics into scars, peripheral nerves, autonomic ganglia, trigger points, glands, and other tissues. Treatment is based on normalizing the dysfunctional autonomic nervous system, which initiates or propagates many chronic ailments. Neural therapy has been used widely by European physicians for over 50 years. Theories of action relating to a dysfunctional autonomic nervous system and chronic pain or illness are discussed.