Chemical radiculitis is an inflammatory condition of the nerve root due to the rupture of the annulus fibrosus and dissemination of disk fluid along the nerve root sheath. The inflammatory component of disk fluid is glycoprotein. The inflammation is a reaction to repeated injuries of the spinal column, as for example, in occupational lifting of heavy loads. Rupture of the annulus fibrosus and liberation of disk fluid into the tissues also evokes circulating antibody response and auto immune reaction. A high titer to glycoprotein at 3 weeks after an acute attack of back pain is evidence of the presence of a significant disk lesion. In selected cases immediate relief from pain occurs after administration of cortisone or a suitable cortisone-derivative. Prolonged rest may be contraindicated because of the risk of formation of radicular adhesions.