The majority of patients suffering from a radiculopathy caused by a herniated nucleus pulposus (HNP) heal spontaneously without surgery or chemonucleolysis. The clinical course of the radiculopathy varies as well as the efficacy of conservative treatment. In some patients the symptoms decline after a week or two; in others the pain may continue for many months or years. Despite an abundant literature there is still a controversy concerning the treatment of radiculopathies related to ruptured lumbar intervertebral discs. Obviously knowledge of the natural history of discal herniation, and of the mechanisms leading to the changes of the extruded discal tissue, would be of great help in planning the therapeutic procedure. The purpose of this article is to review the reliable data concerning the clinical and pathomorphological evolution and the biological mechanisms associated with the morphologic changes of discal herniation.