Enzymatic dissolution of nucleus pulposus by percutaneous injection of a papain preparation is now used frequently to treat lumbosacral disc hernias responsible for resistant sciatica. Mechanisms of action and techniques are reviewed, and the importance of applying strict criteria for indications for use emphasized. The method should be reserved for nerve root sciatica resistant to medical treatment or physiotherapy, and it constitutes the last stage of conservative treatment. Exclusion criteria are mainly "excluded" disc lesions, major dysfunction or associated spinal vertebral canal stenosis. The optimal indication is represented by the subacute disc hernia in the young. This alternative to open surgery in no way compromises the results in case of failure. Results obtained in a personal series of 150 cases are analyzed comparatively with those reported in the literature.