The morphological and histoenzymological changes in spinal neuron and in the spinal ganglia of outbred dogs were analyzed in the epidural administration of 2% solution of lydocaine. The results showed a lack of pathological or structural-and-metabolic changes in the nervous tissue. The morpho-functional reshaping occurring in the spinal cord cells and in the spinal ganglia was in line with that when the 0.9% solution of sodium chloride was in use. The registered changes ranging within the physiological deviations' limits witnessed to a functional reaction of the studied nervous-tissue structures to epidural drugs' injections.