In this research involving 172 cases of acute primary polyradiculoneuritis, the authors draw attention to the frequency and seriousness of the autonomic disorders, notably circulatory disorders (arterial hypertension, bradycardia), water retention, disorders in glucose metabolism. They have found a close correlation between the development of arterial hypertension and levels of VMA and the cathecholamines and between the appearance of hyperglycaemia and the level of urinary 17 OH. Free water clearance is often negative and becomes positive as the paralytic syndrome improves. The biological picture is identical with that brought about by inappropriate secretion of HAD. From the therapeutic point of view, caution is advised in using certain procedures and in prescribing certain drugs.