The changes of urinary excretion after alcohol drinking on 6 normal subjects sweated in a hot chamber were studied. The results are summarized as follows: 1. The urinary minute flow is increased rapidly to maximum about 60 minutes after intake of alcohol, and this is supposed to be originated from the antidiuretic suppressive action on osmoreceptor by ethyl alcohol. 2. Free water clearance and osmolarity of the urine showed the maximal and minimal values respectively at the sane time when the urinary flow is maximal. 3. The concentrations of Na, K and Cl were roughly proportionate to the urinary osmolarity and the minimal values after drinking were diluted to more than 10-fold than those before drinking, but the minute amounts of these ions is decreased only slightly during tile diuresis. 4. The concentrations of urea were decreased less than 10-fold but the minute amounts were rather increased slightly. 5. The diuresis could not excrete whole quantity of fluid intake in the period of 2 hours, and considerable amount of water was still retained in the body.