The author delivered a lecture of the study concerning the influence of oral administration of hot springs upon the functions of the digestive organs made in his institute.<br>A survey carried out in various hot spring resorts in Tohoku Region revealed the fact that about 25% of bathers were the patients of the digestive organs and that only 21.6% of them had been treated with oral administration of hot spring.<br>However, the oral administration of strongly acid spring, concentrated alum vitriol spring, and strong common salt spring, often resulted in the appearance of acute gastroenteritis on administration, and it was necessary to dilute them. In the lecture it was stated that the examination of the cells in gastric juice would be a good indicator for determining the appearance of such symptoms.<br>Both clinical and experimental studies of pH and bacilli colonies in the digestive tract revealed that oral administration of hot spring had a certain degree of effect on pH and bacilli colonies in the stomach, but little effect on those in the intestines. It was made clear, however, that it had some effect on the settlement and the multiplication of bacilli brought in orally.<br>It was also stated in the lecture that a comparison was made of the quantity of gastric secretion with 0.07% caffeine solution for ascertaining the effect of oral administration of hot spring on gastric juice and that curative oral administration, if carried moderately, was effective, regardless of properties of the springs, in normalizing acidity of gastric juice, and in bringing about the disappearance or alleviation of symptoms clinically.<br>As for the effect of oral administration on bile secretion, experiments were performed with dogs. The oral administration of sulfated spring (containing 734mg/l of sodium sulfate) did not necessarily increase bile secretion. This was a natural outcome, because such concentrated sulfated spring as Carlovy in Czechoslovakia and Mergentheim in Germany could not be found in Japan. Therefore, it is rather risky to draw a hasty conclusion that the oral administration of sulfated spring in Japan will directly result in the increase of bile secretion. Attention must be called to the fact that the increase in bile secretion is often brought about by the oral administration of hot springs other than sulfated spring.<br>What the author wanted to emphasize was the fact that in Japan curative oral administration of hot spring was not so popular with bathers as balneological therapy and that studies on this therapeutic method should be made in detail, for Japan is far inferior to Western countries in this respect.