An open trial with the fibrinolytic enchancing agent stanozolol was completed by eighteen patients (14 male) with severe back and radicular pain, despite previous lumbar surgery for prolapsed intervertebral disc. Assessments of their pain, disability and plasma fibrinolytic activity were undertaken before and after 12 or 24 months of therapy. Prior to treatment patients exhibited significant fibrinolytic abnormalities when compared with 84 normal controls; euglobulin clot lysis time (ELT) 442 vs 157 mins and fibrin plate lysis area (FPLA) 61 vs 113 mm2 respectively (p less than 0.01 for both). Stanozolol therapy normalised patients' fibrinolytic activity within three months. Disappointingly there were no concomitant clinical improvements in spinal pain or mobility despite 12 or 24 months of treatment. These results may indicate that perineural fibrosis, once formed, is not amenable to such therapy.