The author investigated variation of non-protein-nitrogen (N-P-N) levels in the blood of patients with gastric ulcer or cancer before and after gastrectomy. The following results were obtained. In the cases of gastric ulcer, N-P-N levels in the blood increased significantly till the 3rd of 4th day after operation, and returned to normalcy within a week in both groups of early rising and thermal bathing, whereas the raised N-P-N levels returned to the former levels in the 2nd week in the control group. In the cases of gastric cancer, in both early rising and thermal bathing groups, N-P-N levels in the blood varied in similar ways as in the cases of gastric ulcer. However, N-P-N in the blood of the control group increased till the 3rd day, and then decreased till the 7th day after operation, but increase was again seen on the 10th day, and then the levels returned to normalcy. From the above findings, the author thinks that early rising and spring bathing after gastrectomy give no bad effect on patients with gastric ulcer and cancer.