The most severe untoward reaction due to blood transfusion is hemolytic reaction which is more often seen in preserved blood transfusion. The cause of this reaction is hemoglobinemia which is resulted by the destruction of red cell. The most important clinical signs of this reaction are the early shock syndrome and late renal failure. To know the pathophysiological pattern of this reaction, the author studied on the experimental hemoglobinemia in dogs. 1. In the experimental hemoglobinemia in dogs, the hemoglobin is excreted in urine when the concentration of hemoglobin in blood plasma is over 150 mg/dl. In the group of alkali-urine There is found the parallel relation between the concentrations in blood plasma and in urine. On the contrary, in the group of acid-urine there is no parallel relation in both. 2. The changes in circulatory volumes; In the early stadium of experimental hemoglobinemia, the circulatory plasma volume decreases markedly, especially in the group of acid-urine. The circulatory blood volume decreases in relative smaller grade than that of plasma volume. This means the concentration of blood. The decreasing of circulatory red cell volume is seen. 3. The constrictin of blood vessels in experimental hemoglobinemia: This change was studied by angiography by 70% jod-pyraceton. In the just after stadium there are shown the marked constriction of A. renalis and relative constriction of A. coeliaca or relative dilatation of A. mesenterica. after 30 minutes there are shwon most marked constriction of all abdominal vessels, especially of A. renalis. The over mentioned constriction of vessels die to experimental hemoglobinemia identify to the marked sympaticotonic state and may be said as re-distribution mechanism of blood to central organs. The cortical shunting of renal circulation is also shown. 4. Liver function; There are seen relative severe disturbance of liver functions (Takada's reaction, Thymol reaction, CaCl(2) reaction etc). The amino-acid curves of blood plasma show the hypofunction of oxygenation in liver, namely anoxia of liver. 5. Renal functions; The renal blood flow and glomerular filtration ratio decrease, but F.F. increases. The non-resorption tatio increases markedly and this means the marked increasing of resorption function. The author concluded these patho-physiological pattern of experimental hemoglobinemia as the following schema.