The role of epidural fibrosis in postoperative sciatica is unclear. Few therapeutic trials have been published. We evaluated the mechanical effects of forceful saline injections through the sacrococcygeal hiatus comparatively with glucocorticoid injections. Methods. Forty-seven patients with postdiscectomy sciatica but no evidence of compression by computed tomography or magnetic resonance imaging were included in a multicenter, randomized, controlled, parallel-group study comparing forceful injections of saline (20 ml) with or without prednisolone acetate (125 mg) to epidural prednisolone acetate (125 mg) alone. Each of the three treatments was given once a month for three consecutive months. Outcome measures were pain severity on a visual analog scale (VAS) and the scores on the Dallas algofunctional self-questionnaire on day 0, day 60, and day 120. Analysis of variance for repeated measures and Student's t test for paired series were used to evaluate the data. Results. Forty-seven patients were evaluated. The VAS score improved significantly between day 0 and day 30 in the glucocorticoid group as compared to the forceful injection group (P = 0.01). No other significant differences were found across the groups. The VAS score improved steadily in the forceful injection group, producing a nearly significant difference on day 120 as compared to baseline (P = 0.08). Conclusion. Forceful epidural injections produced a nonsignificant improvement in postdiscectomy sciatica four months after surgery. Epidural glucocorticoids used alone induced short-lived pain relief.