Many pain therapies have been advocated, but a cost-effective treatment without side effects and complications, is still unavailable. We demonstrated significant antinociception in Sprague Dawley rats following subarachnoid (SAS) and epidural administration of S-(+) -ibuprofen (IB). No motor impariment or behavioral and pathological evidence of neurotoxicity was found in any animal. Briefly, 1 wk after surgical implantation of an SAS catheter through partial lumbar laminectomy, groups of eight rats were given 0.05 ml of normal saline (NS) containing 0.25 mg, 0.5 mg, or 1.5 mg (131.4 uM) of IB into the SAS spaces. NS, 0.05 ml, was used for negative control and 0.025 mg or 0.05 mg (3.3 uM) of preservative-free morphine sulfate (M) for positive control. Tail flick response latency (TFL) was determined before and at 15 min, 30 min, 60 min, 120 min, and 180 min after injection (Figure A). The mean differences between baseline and maximal TFL were analyzed with ananlysis of covariance. P