Two controlled studies for a new epidural, perineural, single-shot, selective nerve root injection with a double-needle approach to the anterior epidural space of the lumbar spinal canal are presented. The results were analysed to determine the effectiveness of the new epidural perineural injection technique. The trial comprised two controlled studies on 182 patients. One study compared prospectively randomized results of patients with lumbar radicular syndromes who received epidural perineural injections (n = 47), conventional posterior epidural injections (n = 40) and, as a control group, paravertebral local anaesthetic (n = 46). A second, prospective, double-blind study compared the effect of epidural perineural injections with triamcinolone (n = 24) and pure saline (n = 25). Epidural perineural injections were more effective than conventional posterior epidural injections. Both epidural groups had better results than the paravertebral local injection group. Epidural perineural injections with steroids (10 mg triamcinolone) were more effective than saline alone. A systemic steroid effect was excluded by additional intramuscular steroid injections in the saline group. There were no severe complications or side effects in any of the three groups. The studies concluded that single-shot epidural perineural injection is effective in the treatment of lumbar radicular pain. It is a "one drop only" therapy to the source of pain.