Catalase activity of the liver was measured in 82 cases with gastric carcinoma as well as in 18 cases with peptic ulcer, resulting in the following conclusions.
1. Liver catalase activity is generally lower in gastric carcinoma cases than in the controls.
2. In gastric carcinoma cases, the lower catalase activities are observed in cases with the more progressed lesions, that is, in cases with the more extended disseminations and in those with the more widely involved lymph nodes, while the activities have little relation to the morphological features of the tumor themselves.
3. In gastric carcinoma cases, the liver catalase activities are comparatively low in those with severe anemia and in those with hypoproteinemia.