The author performed the iron tolerance test, iron absorption test and fractional measurement of depot iron(liver, spleen, kidney, duodenum and bune marrow) on patients of hypoplastic anemia, and obtained the result as follows. 1) Iron tolerance test; The amount of serum iron was generally high, that is, 240 γ % on the average. The increased amount of serum iron in 5 minutes after the intravenous administration of 10 mg. gluferricon was 25 γ % to 133 γ % showing the rather wide movement, and was 64 γ % on the average and this is only 33 % of the normal healthy men’s avererage increased amount. The decreasing amount of serum iron in the two hours was 13 γ % to 64 γ % averaging 34 γ % which was one third that of normal subjects (101 γ % ). Namely the decreasing amount in this case was very slight, and in some cases the decreasing amount in two hours was almost equal with that in 5 minutes. 2) Iron absorption test; The increasing quantities of serum iron in two hours after the administration of 1 g reduced iron was 45 γ % on the average. These were slightly lower than those in normal human beings which were 59 γ % on the average. The serum iron in hypoplastic anemia in 4 hours was 265 γ % and in two hours 256 γ % , namely the former only increased by 3.3 % . On the other hand, the decreasing amount of the serum iron of normal human beings was 32 γ % , which decreases by 16.7 % that in two hours. The decreasing amount of serum iron in 6 hours was 33 γ % in normal human being, 11 γ % in hypoplastic anemia. According to these findings, the author confirmed that the absoption of iron in hypoplastic anemia was not only poor, but also retarded. 3) Fractional measurement of depot iron ; Every fractionation of depot iron in liver, spleen, kidney, bone marrow and duodenum was higher than those in other diseases. P(1) fraction in hypoplastic anemia increased 1.2 ×, 1.4 ×, 2.6 ×, 2.8 × and 1.9 × in each organs respectively than those in other diseases. P(11) fraction exhibited an increase of 2.2 ×, 1.3 ×, 0.7 ×, 3.4 × and 2.0 ×. P(111) fraction increased markedly compared with P(1) and P(11), viz., 6.9 ×, 8.4 ×, 7.1 ×, 10.0 ×, 3.8 ×, S(111) fraction, 9.9 ×, 4.8 ×, 10.0 ×, 18.5 ×, 4.8 × in each organ respectively. Namely, P(111) and S(111) fraction increased remarkably in bone marrow. As mentioned above, the quantity of depot iron in hypoplastic anemia was of surplus, and by the investigation of the movement of each fractionation in the course of the metabolism of non-hemin iron, the author confirmed that P(111) and S(111) exhibited a remarkably risein hypoplastic anemia.