Twenty-two patients with anemia and hypoproteinemia were anesthetized with cyclopropane and the interrelationships between the induction time of anesthesia and the peripheral blood corpuscles or plasma protein were investigated. 1) A reverse interrelationship was seen between the induction time of cyclopropane anesthesia and the water content of the plasma. 2) A parallel interrelationship was seen between the induction time of cyclopropane anesthesia and the total plasma protein. 3) The interrelationships were not found between the induction time of cyclopropane anesthesia and hemoglobin, the erythrocytes, the increased rate of the leucocytes, hemoglobin concentration, hematcrit, the water content of blood and each fraction of the plasmaprotein. 4) In the patients with hypoproteinemia, the stage of anesthesia easily tends to be deeper. Therefore, coutious attention should be called. 5) On the contrary, in the patients with anemia there were not the tendency to be deeper. I imagine cyclopropane is well available for the patients with anemia.