Certain results were obtained to illustrate the possibility of inducing the radiculoneuritis in experimental polio infections in mice. (1) No remarkable inflammatory changes in the spinal root, ganglia, nerve and the sciatic nerve in the adult mice paralysed by intrathecal infection with poliovirus (Mahoney & Lansing strain), and no histological difference between two strains. (2) The previous repeated administration of poliovirus (Mahoney & Lansing strain) intrathecally in the dosis of PD(50) (10(-4), 10(-5)) and 10(-7) or intraperitoneally in the dosis of 10(-1) and the challenge of same virus in the dosis of 10(-2). 10(-4~-6) intrathecal route revealed the mice with paralysis and without visible paralysis. In both mice no detectable histological pictures of polyradiculoneuritis in the spinal root, ganglia, nerve and the sciatic nerve were seen. (3) The reproducible data would seem to indicate the discernible points that the polyradiculoneuritis with Guillain-Barre Syndrome is not affiliated in the major part to the primary affection or repeated inoculations of poliovirus of the neuroallergic basis of pathogenesis.