THE ETIOLOGY of idiopathic polyneuritis (Landry-Guillain-Barré syndrome) is unknown. Perhaps half the cases give a history of an antecedent infectious illness. Usually this has occurred two to three weeks before the neuritic symptoms begin. The antecedent illness is often described as influenza-like, although sometimes backache and diarrhea are prominent. How preceding illness is linked to subsequent polyneuritis is by no means clear, but it seems probable that it somehow acts as a precipitating event. Other precipitating events leading to polyneuritis have been recorded. Prolonged fever therapy, in the days when it was practiced, was followed occasionally by a polyneuritis after a latent interval of about two weeks.1 Polyneuritis has also been seen occasionally after prophylactic antirabies vaccination.2 In recent years we have seen six cases of idiopathic polyneuritis as a sequel to a surgical procedure. In two instances postmortem examination of peripheral nerve confirmed the diagnosis of