Epidural steroid therapy has been well-established for the treatment of sciatica and low back pain. Disappointing results following surgical decompression or discectomy pain owing for to nerve root compression have led to trials of corticosteroids injected either systemically or into the intrathecal or epidural space to treat intervertebral disc. Epidural steroid is less effective in the patients with low back pain who have a history of surgical operation, so that the use of epidural morphine and methylprednisolone has been advocated for the amelioration of chronic low back pain in the post-laminectomy pain("failed back") syndrome over the past several years. We treated 47 patients with low back pain who had a history of one or two surgical procedures. We concluded that epidural steroid therapy is less effective in the patients with "failed back" syndrome than in the virgin back furthermore, there is a greater risk of complication such as inadvertent dural puncture and corresponding motor paralysis and headache.