Nearly all the investigations on abnormalities of the gastric and duodenal motility in acute hepatitis have depended on fluoroscopic findings. However, the fluoroscopic method has disadvantages in that it is not possible to observe the motility of the stomach and duodenum for any length of time nor can it afford quantitative estimation of the motility, resulting in the subjective decision of the examiner, In view of this, the author took "balloon kymographic recordings" of antral gastric and duodenal motility in 6 normal persons, 10 cases of acute hepatitis, 12 of chronic hepatitis, and 6 of recurrent chronic hepatitis. On the basis of these recordings, the general pattern of motility, description of waves and analysis of the records are given in the present communication. 1. In the normal control group the total activity (percent of time present) of antral gastric motility proved to be 38.2±2.6%. Of it 23.5±2.5% was consisted of the twenty-second rhythm described by Carlson. while the rest was composed of nonrhythmic waves. The total activity of duodenal motility was 60.6±2.7%, and the waves seen in the records were classified into two types, designated Types Ⅰ and Ⅲ. The percent of time taken by nonrhythmic Type Ⅰ wave was 31.3±2.3% and that by Type Ⅲ wave, 27.2±2.3%. 2. In the icteric stage of acute hepatitis, the total activity was decreased both in antrum pylori and duodenum and mean amplitude (cm water) tended to rise, while the standard deviation of mean amplitude was large. In the motility pattern of duodenum there was recognized a rising tendency in the basal pressure of Type Ⅲ wave. At the recovery stage where jaundice had disappeared, both the general pattern of motility and the total activity in antrum pylori and duodenum returned normal. 3. In chronic hepatitis there could be observed no significant dlifference from normal control group. In recurrent chronic hepatitis there could be seen a decrease in the total activity just as in the case of acute hepatitis at icteric stage. However, there was no significant difference in mean amplitude. 4. In two of the ten cases with acute hepatitis at icteric stage and in two of the six cases with recurrent chronic hepatitis, the balloon did not pass through pylorus, and this is judged to be due to motility abnormality of pylorus. 5. Mean duration of the waves as observable in motility patterns of antrum pylori and duodenum proved to be the same both in acute and chronic hepatitis as well as in normal control. 6. The reduction of motility observed in stomach and duodenum may be pointed out as one of the causes for discomfort of the upper abdomen in acute hepatitis at icteric stage and in chronic hepatitis at recurent stage.