(1) The search was made to differentiate the possibilities of inducing the neuroallergy by infection in the case of polyradiculoneuritis with viruses of coxsackie group, strain Okumoto (A-2), Dohi (A-19) and Saragai (B-1) which were isolated from the patients with the polyradiculoneuritis showing Guillain-Barre Syndrome. (2) (A) Previous repeated administration of these three strains of coxsackie virus in the adult mice through intraperitoneal route and the challenge of identical virus intrathecally. (B) Similar repeated administration of PD(50) of poliovirus (Mahoney or Lansing strain) through intrathecal route and the challenge of coxsackie virus Okumoto Strain through same route to survived and sensitized mice after previous inoculations. The observation for 1 month revealed no significant signs of paralysis. Histologically no discernible picture of polyradiculoneuritis in the spinal root, ganglia, nerve and the ischias was clarified. (3) No acceptable evidence of the presence of neuroallergy by infection experimentally made in the above strains was obtained through the trials with coxsackie virus and polio virus in the mode of repeated inoculations.