The purpose of this study is to determine the:

Primary end point

• change of Total symptom score

Secondary end point

• neurological test

total symptom score shall be calculated from the data of burning, numbness, stabbing pain, paraesthesiae.

Inclusion Criteria:

• Diabetes mellitus (Type I or II), as defined by the American Diabetes Association, 1997, lasting 1 year and is well-controlled.
• Patient with symmetric sensory-motor Diabetic Neuropathy which is above stage 2
• Result of pin-prick test is 'absent' or 'reduced'
• HbA1C <10%
• Total Symptom Score ≥ 4 points
• At least 1 of the 4 symptoms of the TSS must have occurred continuously over the last 3 months.
• Patient over 19 years of age
• Female who is postmenopausal or is willing to use an effective method of contraception during the study (Effective method=IUD, spermicide with condom, abstinence) or is surgically sterile (underwent a total hysterectomy or bilateral tubal ligation).

Exclusion Criteria:

• Patient who has Proximal asymmetric neuropathy, cranial neuropathies, truncal radiculopathy, diabetic plexopathies, acute or active mononeuropathies (cranial neuropathies, post-herpes neuralgias)
• Patient who has Neuropathy from alcohol, drug (cisplatin, taxol , etcs), malignant cancer or has a medical history of nerve system disease such as Parkinson's disease/ epilepsy/ Multiple sclerosis, etcs.
• Patient who has nerve system disease which can cause sensory loss Myopathy of any cause.
• Peripheral vascular disease severe enough to cause ischemic ulcers or limb ischemia.
• Patients with diabetic proliferating retinopathy requiring immediately therapy and impending blindness.
• Patients with any active neoplastic disease except benign tumor or nonrecurrent malignant tumor for 5 years.
• Patients with clinically significant cardiac, pulmonary, gastrointestinal, haematological, or endocrine disease that may confound interpretation of the study results or prevent the patient from completing the study.
• Patients with atrial fibrillation.
• Patients who have had organ transplants of any kind.
• Patients with significant hepatic or renal disease (AST, ALT or GGT >2 times normal, serum creatinine >1.8 mg/dL (>159 mmol/l) for males or >1.6 mg/dL (>141 mmol/l) for females).
• Patients with a recent history (within last 12 months) of drug or alcohol abuse.
• Use of any investigational drug (participation in a clinical trial) within last 1 month.
• History of severe or anaphylactic reaction to drugs, sulfur or biologic products.
• Recent (within last 3 months) ketoacidosis or hypoglycaemia, necessitating hospital admission.
• Existing foot ulcers.
• Pregnant or lactating females
• History of allergic reaction to the study medication or its excipients.
• Psychiatric, psychological, or behavioural symptoms that would interfere with the patient's ability to participate in the trial.
• Patient who is not suitable to trial by investigator judgment.
• Patient who does not write informed consent prior to start of trial and cannot comply with the trial requirements.
• Antioxidant therapy (vitamins E > 400 IU, C > 200 mg, and beta-Carotene > 30 mg) or pentoxyphylline within last 1 month before start of trial.
• Use of thioctic acid (> 50 mg), evening primrose oil or any other gamma-linolenic acid containing substance within the last 3 months.
• Use of analgesic within >5times of a half-life before administration of investigational medication.
• Use of anticonvulsants(include Pregabalin), antidepressants within 4 weeks before administration of investigational medication.