1) After the administration of Nitrolime or Antabuse to rabbits, narcosis induced by itravenous injection of alcohol is remarkably intensified. Animals subjected to both kinds of treamtment show a much higher concentration of acetaldehyde in blood than do controls. 2) Immediately after i.v. injection of alcohol, Nitrolime-or Antabuse-treated animals (inbred albino rats (Wistar S.)) show a much higher concentration of alcohol in brain and liver but lower in muscle than do untreated animals, but formation of acetaldehyde in blood then is not greatly increased. The intensified alcohol narcosis, which is then induced, is probably due to the increased concentration of alcohol in brain. 3) Nitrolime-prepared human subjects are more sensitive to alcohol ; after intake of alcohol they show a much higher concentration of acetaldehyde in blood than do untreated subjects. Severe clinical reactions which are occasionally seen during Nitrolime-alcohol reaction were not seen during Nitrolime-alcohol reaction, and no pathological change was seen in EKG or in liver and kidney, but until sufficient data are accumulated, administration of Nitrolime should be considered as a dangerous procedure. Only further clinical trial can establish its uses and limitation.