Vagal neuropathy in chronic alcoholics seems more common than supposed and its reversibility and relationship with alcohol intake and nutritional status remain obscure. We embarked upon a study of a series of 70 chronic alcoholics in whom reliable alcoholism history, nutritional status evaluation and cardiovascular reflex tests were performed at the beginning of abstinence. Moreover, an electrophysiological study of peripheral nerves was carried out. Five out of 70 patients had symptoms related to autonomic neuropathy. Fourteen alcoholics presented abnormal indices in the deep breathing test (DBT) performed, including the five patients with clinical manifestations. A strong correlation between DBT indices and total lifetime ethanol intake and motor conduction velocity of lower limbs (MCV) was observed. No gross evidence of malnutrition was detected in the alcoholics and the transketolase erythrocyte activity was normal in all but one. Since the MCV also correlated with total lifetime ethanol intake, it appears that ethanol may exercise a dose-related toxic effect on both the autonomic and peripheral nervous systems. Finally, 12 of 14 patients with abnormal DBT index were re-evaluated one year later. Eleven who reported complete ethanol abstinence presented an improvement of this index and nine of them reached the normal range. Three of four patients with clinical manifestations reported an improvement of the symptoms. Thus, vagal neuropathy may reverse in most of the patients who manage to maintain ethanol abstinence.