The purpose of this study was to examine the antitumor effect of strangulation to cease blood flow on tumor tissue. AH130 cells were implanted in the mesentery near the ileocecal portion of rats 10 days previously. A recovery rate of blood flow was observed in the tumor tissue and normal tissue (cecal wall) after reperfusion with a charge-coupled device microscope (CCD). Five days after reperfusion, the tumor volume ratio was measured. On the death or sacrifice of the animals, the tumor necrotic area ratio was examined. The vascular morphology and the changes of a recovery rate of blood flow after reperfusion differed from the tumor tissue and the normal tissue by CCD observation. In the 15-min and 30-min groups, the tumor vessels underwent little or no destruction, with only a few showing a cessation of blood flow. However, the 60-min and 90-min groups showed a cessation of blood flow and hemorrhage due to vascular destruction in many vessels, and few vessels showed intact blood flow. In 60 and 90-minutes strangulated groups, a recovery rate of blood flow after 60 minutes was lower in tumor tissue than in the normal tissue. The tumor volume ratio decreased more in the 60 and 90-minutes strangulated groups than in the non-strangulated group and the tumor necrotic area increased more in all strangulated groups than in the non-strangulated group. These findings suggest that strangulation for ischemia for 60-90 minutes injures the tumor tissue and shows the antitumor effect.