Experiments were carried out on 22 mongrel dogs (12-20 kg). Group 1 consisted of 5 dogs to which prosidol in a dose of 0.65 mg/kg was injected epidurally; group 2, 5 dogs, clofelin (6.5 micrograms/kg) epidurally; group 3, 5 dogs, prosidol (0.65 mg/kg) + clofelin (6.5 micrograms/kg) epidurally. Control groups were as follows: 1) 5 intact dogs; 2) 2 dogs epidurally injected with 0.9% normal saline. Analysis of the spinal cord and ganglia in control groups showed no dystrophic changes in neurons. After epidural injections of prosidol, clofelin, or both only solitary cells with degenerative changes were detected or none at all. Nissle granules were evenly distributed in the cytoplasm of anterior and posterior spinal horn neurons in all control and experimental animals. The majority of ganglious cells in control and experiment had the nucleus and nucleolus. Hence, morphological analysis showed that epidural injection of prosidol, clofelin, and a combination of both caused no degenerative or necrobiotic changes in the anterior and posterior spinal horn neurons and in ganglious cells of spinal ganglia.