Anesthetized cats were subjected to standardized cervical spinal trauma produced by a modification of the Allen weight-dropping method. One hour after injury, animals were randomly allocated to one of three treatment groups, in which they received 1) saline, 2) naloxone, or 3) combined treatment, consisting of indomethacin, heparin, and prostacyclin (PGI2). Treatment was continued for 4 hours. Neurological function was evaluated weekly by a neurologist unaware of the treatment group, and was graded by means of a scale modified from that of Tarlov. Functional recovery in animals receiving combined drug therapy was significantly better than in saline-treated control animals, and was similar to that observed in naloxone-treated animals. The findings are discussed with respect to "blood-damaged tissue interaction" and may have implications both with regard to the pharmacological management of acute spinal injury and to the mechanism of action of opiate antagonists.