Recently, intravenous lidocaine has been reported to relieve chronic pain and to suppress the spontaneous abnormal ectopic discharge in injured nerve. Interest in the use of these modalities has been stimulated by animal researches of neuropathic pain syndromes. We performed this study to evaluate the analgesic responses and the side effects of intravenous(IV) irifusion of lidocaine used in chronic pain patients. Patients received 5 mg/kg of lidocaine, mixed in 150 mL over 40 minutes. The analgesic efficacy was evaluated in 20, 40, 60 minutes after the start of the initial IV lidocaine infusion, by a numeric rating scales (NRS) scores. The responders were received the repeated infusions at one week interval. The results were as follows; 1. Mean NRS scores was 6.7+/-1.9 before the infusion, and changed to 4.2, 2.7, 2.6, in 20,40,60 minutes after the start of the initial IV lidocaine infusion. 2. Eight of ten patients were responders during initial IV lidocaine infusion, and two patients were nonresponders. During the series of repeated lidocaine infusions to eight responders, six were partial relief, and two were complete relief of their pain without any medication. The diagnoses in responders were diabetic neuropathy, ischemic neuropathy, traumatic neuropathy, causalgia, reflex sympathetic dystrophy, erythromelalgia, and spinal stenosis. 3. The side effects, including sedation, dizziness, slurred speech, circumoral numbness, and lightheadedness, were not serious during the period of infusion. The conclusion is that repeated intravenous lidocaine infusions would be effective in the management of chronic pain states. But it needs more studies on the method of infusion and the safety of these modalities.